81475816 has 32 divisors (see below), whose sum is σ = 156723840. Its totient is φ = 39691008.

The previous prime is 81475799. The next prime is 81475853. The reversal of 81475816 is 61857418.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126391 + ... + 127033.

It is an arithmetic number, because the mean of its divisors is an integer number (4897620).

Almost surely, 2^81475816 is an apocalyptic number.

It is an amenable number.

81475816 is a deficient number, since it is larger than the sum of its proper divisors (75248024).

81475816 is a wasteful number, since it uses less digits than its factorization.

81475816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1033 (or 1029 counting only the distinct ones).

The product of its digits is 53760, while the sum is 40.

The square root of 81475816 is about 9026.3955153760. The cubic root of 81475816 is about 433.5204341281.

The spelling of 81475816 in words is "eighty-one million, four hundred seventy-five thousand, eight hundred sixteen".