81623522 has 4 divisors (see below), whose sum is σ = 122435286. Its totient is φ = 40811760.

The previous prime is 81623501. The next prime is 81623539. The reversal of 81623522 is 22532618.

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

It can be written as a sum of positive squares in only one way, i.e., 57896881 + 23726641 = 7609^2 + 4871^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20405879 + ... + 20405882.

Almost surely, 2^81623522 is an apocalyptic number.

81623522 is a deficient number, since it is larger than the sum of its proper divisors (40811764).

81623522 is a wasteful number, since it uses less digits than its factorization.

81623522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40811763.

The product of its digits is 5760, while the sum is 29.

The square root of 81623522 is about 9034.5737032801. The cubic root of 81623522 is about 433.7822497040.

The spelling of 81623522 in words is "eighty-one million, six hundred twenty-three thousand, five hundred twenty-two".