81615633 has 16 divisors (see below), whose sum is σ = 118867392. Its totient is φ = 49400000.

The previous prime is 81615631. The next prime is 81615713. The reversal of 81615633 is 33651618.

It is a cyclic number.

It is not a de Polignac number, because 81615633 - 2¹ = 81615631 is a prime.

It is a super-2 number, since 2×81615633² = 13322223099981378, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 81615594 and 81615603.

It is not an unprimeable number, because it can be changed into a prime (81615631) 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, 41983 + ... + 43883.

It is an arithmetic number, because the mean of its divisors is an integer number (7429212).

Almost surely, 2^81615633 is an apocalyptic number.

It is an amenable number.

81615633 is a deficient number, since it is larger than the sum of its proper divisors (37251759).

81615633 is a wasteful number, since it uses less digits than its factorization.

81615633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3216.

The product of its digits is 12960, while the sum is 33.

The square root of 81615633 is about 9034.1370921633. The cubic root of 81615633 is about 433.7682740822.

The spelling of 81615633 in words is "eighty-one million, six hundred fifteen thousand, six hundred thirty-three".