81924554 has 4 divisors (see below), whose sum is σ = 122886834. Its totient is φ = 40962276.

The previous prime is 81924539. The next prime is 81924571. The reversal of 81924554 is 45542918.

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., 51509329 + 30415225 = 7177^2 + 5515^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20481137 + ... + 20481140.

Almost surely, 2^81924554 is an apocalyptic number.

81924554 is a deficient number, since it is larger than the sum of its proper divisors (40962280).

81924554 is a wasteful number, since it uses less digits than its factorization.

81924554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40962279.

The product of its digits is 57600, while the sum is 38.

The square root of 81924554 is about 9051.2183710261. The cubic root of 81924554 is about 434.3148663302.

The spelling of 81924554 in words is "eighty-one million, nine hundred twenty-four thousand, five hundred fifty-four".