81788553 has 48 divisors (see below), whose sum is σ = 148801536. Its totient is φ = 42052320.

The previous prime is 81788527. The next prime is 81788561. The reversal of 81788553 is 35588718.

It is a happy number.

81788553 is a `hidden beast` number, since 8 + 17 + 88 + 553 = 666.

It is not a de Polignac number, because 81788553 - 2⁸ = 81788297 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81788499 and 81788508.

It is not an unprimeable number, because it can be changed into a prime (81788503) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 73600 + ... + 74702.

It is an arithmetic number, because the mean of its divisors is an integer number (3100032).

Almost surely, 2^81788553 is an apocalyptic number.

It is an amenable number.

81788553 is a deficient number, since it is larger than the sum of its proper divisors (67012983).

81788553 is a wasteful number, since it uses less digits than its factorization.

81788553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234 (or 1231 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 81788553 is about 9043.7023944842. The cubic root of 81788553 is about 434.0744012974.

The spelling of 81788553 in words is "eighty-one million, seven hundred eighty-eight thousand, five hundred fifty-three".