81587374 has 16 divisors (see below), whose sum is σ = 135501696. Its totient is φ = 36531000.

The previous prime is 81587357. The next prime is 81587419. The reversal of 81587374 is 47378518.

It is a self number, because there is not a number n which added to its sum of digits gives 81587374.

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, 26202 + ... + 29149.

It is an arithmetic number, because the mean of its divisors is an integer number (8468856).

Almost surely, 2^81587374 is an apocalyptic number.

81587374 is a deficient number, since it is larger than the sum of its proper divisors (53914322).

81587374 is a wasteful number, since it uses less digits than its factorization.

81587374 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55431.

The product of its digits is 188160, while the sum is 43.

The square root of 81587374 is about 9032.5729446266. The cubic root of 81587374 is about 433.7182049463.

Subtracting from 81587374 its reverse (47378518), we obtain a triangular number (34208856 = T₈₂₇₁).

The spelling of 81587374 in words is "eighty-one million, five hundred eighty-seven thousand, three hundred seventy-four".