81499137 has 8 divisors (see below), whose sum is σ = 108815520. Its totient is φ = 54257760.

The previous prime is 81499133. The next prime is 81499157. The reversal of 81499137 is 73199418.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81499137 - 2² = 81499133 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81499133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16164 + ... + 20597.

It is an arithmetic number, because the mean of its divisors is an integer number (13601940).

Almost surely, 2^81499137 is an apocalyptic number.

It is an amenable number.

81499137 is a deficient number, since it is larger than the sum of its proper divisors (27316383).

81499137 is a wasteful number, since it uses less digits than its factorization.

81499137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37503.

The product of its digits is 54432, while the sum is 42.

The square root of 81499137 is about 9027.6872453580. The cubic root of 81499137 is about 433.5617926811.

The spelling of 81499137 in words is "eighty-one million, four hundred ninety-nine thousand, one hundred thirty-seven".