81493408 has 12 divisors (see below), whose sum is σ = 160440210. Its totient is φ = 40746688.

The previous prime is 81493387. The next prime is 81493411. The reversal of 81493408 is 80439418.

It can be written as a sum of positive squares in only one way, i.e., 76947984 + 4545424 = 8772^2 + 2132^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1273303 + ... + 1273366.

Almost surely, 2^81493408 is an apocalyptic number.

It is an amenable number.

81493408 is a deficient number, since it is larger than the sum of its proper divisors (78946802).

81493408 is a wasteful number, since it uses less digits than its factorization.

81493408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2546679 (or 2546671 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 81493408 is about 9027.3699381381. The cubic root of 81493408 is about 433.5516333355.

The spelling of 81493408 in words is "eighty-one million, four hundred ninety-three thousand, four hundred eight".