81137552 has 10 divisors (see below), whose sum is σ = 157204038. Its totient is φ = 40568768.

The previous prime is 81137533. The next prime is 81137561. The reversal of 81137552 is 25573118.

It can be written as a sum of positive squares in only one way, i.e., 81072016 + 65536 = 9004^2 + 256^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2535533 + ... + 2535564.

Almost surely, 2^81137552 is an apocalyptic number.

It is an amenable number.

81137552 is a deficient number, since it is larger than the sum of its proper divisors (76066486).

81137552 is a wasteful number, since it uses less digits than its factorization.

81137552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5071105 (or 5071099 counting only the distinct ones).

The product of its digits is 8400, while the sum is 32.

The square root of 81137552 is about 9007.6385362647. The cubic root of 81137552 is about 432.9196514895.

The spelling of 81137552 in words is "eighty-one million, one hundred thirty-seven thousand, five hundred fifty-two".