81615099 has 4 divisors (see below), whose sum is σ = 108820136. Its totient is φ = 54410064.

The previous prime is 81615097. The next prime is 81615103. The reversal of 81615099 is 99051618.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81615099 - 2¹ = 81615097 is a prime.

It is a super-2 number, since 2×81615099² = 13322048769559602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81615091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13602514 + ... + 13602519.

It is an arithmetic number, because the mean of its divisors is an integer number (27205034).

Almost surely, 2^81615099 is an apocalyptic number.

81615099 is a deficient number, since it is larger than the sum of its proper divisors (27205037).

81615099 is a wasteful number, since it uses less digits than its factorization.

81615099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27205036.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 81615099 is about 9034.1075375490. The cubic root of 81615099 is about 433.7673280512.

The spelling of 81615099 in words is "eighty-one million, six hundred fifteen thousand, ninety-nine".