81506710 has 16 divisors (see below), whose sum is σ = 153091296. Its totient is φ = 31185088.

The previous prime is 81506693. The next prime is 81506771. The reversal of 81506710 is 1760518.

It is a happy number.

It is a congruent number.

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, 176959 + ... + 177418.

It is an arithmetic number, because the mean of its divisors is an integer number (9568206).

Almost surely, 2^81506710 is an apocalyptic number.

81506710 is a deficient number, since it is larger than the sum of its proper divisors (71584586).

81506710 is a wasteful number, since it uses less digits than its factorization.

81506710 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354407.

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 81506710 is about 9028.1066675134. The cubic root of 81506710 is about 433.5752212968.

The spelling of 81506710 in words is "eighty-one million, five hundred six thousand, seven hundred ten".