81597633 has 16 divisors (see below), whose sum is σ = 117390336. Its totient is φ = 50117760.

The previous prime is 81597601. The next prime is 81597643. The reversal of 81597633 is 33679518.

It is not a de Polignac number, because 81597633 - 2⁵ = 81597601 is a prime.

It is a super-2 number, since 2×81597633² = 13316347422405378, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81597643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22368 + ... + 25758.

It is an arithmetic number, because the mean of its divisors is an integer number (7336896).

Almost surely, 2^81597633 is an apocalyptic number.

It is an amenable number.

81597633 is a deficient number, since it is larger than the sum of its proper divisors (35792703).

81597633 is a wasteful number, since it uses less digits than its factorization.

81597633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4024.

The product of its digits is 136080, while the sum is 42.

The square root of 81597633 is about 9033.1408159067. The cubic root of 81597633 is about 433.7363831208.

The spelling of 81597633 in words is "eighty-one million, five hundred ninety-seven thousand, six hundred thirty-three".