81773244 has 36 divisors (see below), whose sum is σ = 236234544. Its totient is φ = 23363712.

The previous prime is 81773239. The next prime is 81773249. The reversal of 81773244 is 44237718.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81773239) and next prime (81773249).

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81773199 and 81773208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81773249) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161997 + ... + 162500.

Almost surely, 2^81773244 is an apocalyptic number.

81773244 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

81773244 is an abundant number, since it is smaller than the sum of its proper divisors (154461300).

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

81773244 is a wasteful number, since it uses less digits than its factorization.

81773244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324514 (or 324509 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 81773244 is about 9042.8559647934. The cubic root of 81773244 is about 434.0473165794.

The spelling of 81773244 in words is "eighty-one million, seven hundred seventy-three thousand, two hundred forty-four".