1997835840 has 1260 divisors, whose sum is σ = 9785767068. Its totient is φ = 383201280.

The previous prime is 1997835751. The next prime is 1997835859. The reversal of 1997835840 is 485387991.

It can be written as a sum of positive squares in 2 ways, for example, as 491774976 + 1506060864 = 22176^2 + 38808^2 .

It is a tau number, because it is divible by the number of its divisors (1260).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 153679674 + ... + 153679686.

Almost surely, 2^1997835840 is an apocalyptic number.

1997835840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1997835840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4892883534).

1997835840 is an abundant number, since it is smaller than the sum of its proper divisors (7787931228).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1997835840 is a wasteful number, since it uses less digits than its factorization.

1997835840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The square root of 1997835840 is about 44697.1569565672. The cubic root of 1997835840 is about 1259.4664407577.

The spelling of 1997835840 in words is "one billion, nine hundred ninety-seven million, eight hundred thirty-five thousand, eight hundred forty".