81532657 has 8 divisors (see below), whose sum is σ = 82243584. Its totient is φ = 80825088.

The previous prime is 81532621. The next prime is 81532669. The reversal of 81532657 is 75623518.

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

It is a cyclic number.

It is not a de Polignac number, because 81532657 - 2¹¹ = 81530609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81532757) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73368 + ... + 74470.

It is an arithmetic number, because the mean of its divisors is an integer number (10280448).

Almost surely, 2^81532657 is an apocalyptic number.

It is an amenable number.

81532657 is a deficient number, since it is larger than the sum of its proper divisors (710927).

81532657 is a wasteful number, since it uses less digits than its factorization.

81532657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1679.

The product of its digits is 50400, while the sum is 37.

The square root of 81532657 is about 9029.5435654301. The cubic root of 81532657 is about 433.6212248005.

The spelling of 81532657 in words is "eighty-one million, five hundred thirty-two thousand, six hundred fifty-seven".