81635865099 has 64 divisors (see below), whose sum is σ = 115734528000. Its totient is φ = 51111889920.

The previous prime is 81635865089. The next prime is 81635865109. The reversal of 81635865099 is 99056853618.

It is an interprime number because it is at equal distance from previous prime (81635865089) and next prime (81635865109).

It is not a de Polignac number, because 81635865099 - 2¹⁷ = 81635734027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81635865089) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 170429542 + ... + 170430020.

It is an arithmetic number, because the mean of its divisors is an integer number (1808352000).

Almost surely, 2^81635865099 is an apocalyptic number.

81635865099 is a deficient number, since it is larger than the sum of its proper divisors (34098662901).

81635865099 is a wasteful number, since it uses less digits than its factorization.

81635865099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908.

The product of its (nonzero) digits is 13996800, while the sum is 60.

The spelling of 81635865099 in words is "eighty-one billion, six hundred thirty-five million, eight hundred sixty-five thousand, ninety-nine".