81205976 has 8 divisors (see below), whose sum is σ = 152261220. Its totient is φ = 40602984.

The previous prime is 81205967. The next prime is 81205987. The reversal of 81205976 is 67950218.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×81205976² = 13188821076225152, which contains 22 as substring.

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, 5075366 + ... + 5075381.

Almost surely, 2^81205976 is an apocalyptic number.

It is an amenable number.

81205976 is a deficient number, since it is larger than the sum of its proper divisors (71055244).

81205976 is a wasteful number, since it uses less digits than its factorization.

81205976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10150753 (or 10150749 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 81205976 is about 9011.4358456353. The cubic root of 81205976 is about 433.0413122600.

The spelling of 81205976 in words is "eighty-one million, two hundred five thousand, nine hundred seventy-six".