81659654 has 4 divisors (see below), whose sum is σ = 122489484. Its totient is φ = 40829826.

The previous prime is 81659597. The next prime is 81659671. The reversal of 81659654 is 45695618.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20414912 + ... + 20414915.

It is an arithmetic number, because the mean of its divisors is an integer number (30622371).

Almost surely, 2^81659654 is an apocalyptic number.

81659654 is a deficient number, since it is larger than the sum of its proper divisors (40829830).

81659654 is a wasteful number, since it uses less digits than its factorization.

81659654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40829829.

The product of its digits is 259200, while the sum is 44.

The square root of 81659654 is about 9036.5731336608. The cubic root of 81659654 is about 433.8462472206.

The spelling of 81659654 in words is "eighty-one million, six hundred fifty-nine thousand, six hundred fifty-four".