81507737432 has 32 divisors (see below), whose sum is σ = 166771472400. Its totient is φ = 37037616000.

The previous prime is 81507737431. The next prime is 81507737449. The reversal of 81507737432 is 23473770518.

It is a super-2 number, since 2×81507737432² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81507737431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150194 + ... + 430782.

Almost surely, 2^81507737432 is an apocalyptic number.

It is an amenable number.

81507737432 is an abundant number, since it is smaller than the sum of its proper divisors (85263734968).

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

81507737432 is a wasteful number, since it uses less digits than its factorization.

81507737432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283907 (or 283903 counting only the distinct ones).

The product of its (nonzero) digits is 987840, while the sum is 47.

The spelling of 81507737432 in words is "eighty-one billion, five hundred seven million, seven hundred thirty-seven thousand, four hundred thirty-two".