81556378 has 12 divisors (see below), whose sum is σ = 129954942. Its totient is φ = 38379200.

The previous prime is 81556373. The next prime is 81556411. The reversal of 81556378 is 87365518.

It can be written as a sum of positive squares in 3 ways, for example, as 78269409 + 3286969 = 8847^2 + 1813^2 .

It is not an unprimeable number, because it can be changed into a prime (81556373) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 69973 + ... + 71128.

Almost surely, 2^81556378 is an apocalyptic number.

81556378 is a deficient number, since it is larger than the sum of its proper divisors (48398564).

81556378 is a wasteful number, since it uses less digits than its factorization.

81556378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141137 (or 141120 counting only the distinct ones).

The product of its digits is 201600, while the sum is 43.

The square root of 81556378 is about 9030.8569914488. The cubic root of 81556378 is about 433.6632731121.

The spelling of 81556378 in words is "eighty-one million, five hundred fifty-six thousand, three hundred seventy-eight".