1988190881 has 4 divisors (see below), whose sum is σ = 2012145072. Its totient is φ = 1964236692.

The previous prime is 1988190823. The next prime is 1988190899. The reversal of 1988190881 is 1880918891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1880918891 = 1049 ⋅1793059.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1988190881 is a prime.

It is a super-2 number, since 2×1988190881² = 7905805958583112322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1988190811) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 11976971 + ... + 11977136.

It is an arithmetic number, because the mean of its divisors is an integer number (503036268).

Almost surely, 2^1988190881 is an apocalyptic number.

It is an amenable number.

1988190881 is a deficient number, since it is larger than the sum of its proper divisors (23954191).

1988190881 is an equidigital number, since it uses as much as digits as its factorization.

1988190881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23954190.

The product of its (nonzero) digits is 331776, while the sum is 53.

The square root of 1988190881 is about 44589.1341135932. The cubic root of 1988190881 is about 1257.4363935908.

The spelling of 1988190881 in words is "one billion, nine hundred eighty-eight million, one hundred ninety thousand, eight hundred eighty-one".