81415137 has 4 divisors (see below), whose sum is σ = 108553520. Its totient is φ = 54276756.

The previous prime is 81415121. The next prime is 81415141. The reversal of 81415137 is 73151418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81415137 - 2⁴ = 81415121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81415157) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13569187 + ... + 13569192.

It is an arithmetic number, because the mean of its divisors is an integer number (27138380).

Almost surely, 2^81415137 is an apocalyptic number.

It is an amenable number.

81415137 is a deficient number, since it is larger than the sum of its proper divisors (27138383).

81415137 is a wasteful number, since it uses less digits than its factorization.

81415137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27138382.

The product of its digits is 3360, while the sum is 30.

The square root of 81415137 is about 9023.0336916139. The cubic root of 81415137 is about 433.4127861544.

It can be divided in two parts, 814 and 15137, that added together give a palindrome (15951).

The spelling of 81415137 in words is "eighty-one million, four hundred fifteen thousand, one hundred thirty-seven".