81453537 has 12 divisors (see below), whose sum is σ = 128351184. Its totient is φ = 49365720.

The previous prime is 81453529. The next prime is 81453553. The reversal of 81453537 is 73535418.

81453537 is a `hidden beast` number, since 81 + 45 + 3 + 537 = 666.

It is not a de Polignac number, because 81453537 - 2³ = 81453529 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81453517) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 411283 + ... + 411480.

It is an arithmetic number, because the mean of its divisors is an integer number (10695932).

Almost surely, 2^81453537 is an apocalyptic number.

It is an amenable number.

81453537 is a deficient number, since it is larger than the sum of its proper divisors (46897647).

81453537 is a wasteful number, since it uses less digits than its factorization.

81453537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822780 (or 822777 counting only the distinct ones).

The product of its digits is 50400, while the sum is 36.

The square root of 81453537 is about 9025.1613281980. The cubic root of 81453537 is about 433.4809161349.

The spelling of 81453537 in words is "eighty-one million, four hundred fifty-three thousand, five hundred thirty-seven".