81137530 has 8 divisors (see below), whose sum is σ = 146047572. Its totient is φ = 32455008.

The previous prime is 81137527. The next prime is 81137533. The reversal of 81137530 is 3573118.

It is an interprime number because it is at equal distance from previous prime (81137527) and next prime (81137533).

It can be written as a sum of positive squares in 2 ways, for example, as 81054009 + 83521 = 9003^2 + 289^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81137533) 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, 4056867 + ... + 4056886.

Almost surely, 2^81137530 is an apocalyptic number.

81137530 is a deficient number, since it is larger than the sum of its proper divisors (64910042).

81137530 is a wasteful number, since it uses less digits than its factorization.

81137530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8113760.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 81137530 is about 9007.6373150788. The cubic root of 81137530 is about 432.9196123615.

The spelling of 81137530 in words is "eighty-one million, one hundred thirty-seven thousand, five hundred thirty".