81739550 has 12 divisors (see below), whose sum is σ = 152035656. Its totient is φ = 32695800.

The previous prime is 81739513. The next prime is 81739571. The reversal of 81739550 is 5593718.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 817346 + ... + 817445.

It is an arithmetic number, because the mean of its divisors is an integer number (12669638).

Almost surely, 2^81739550 is an apocalyptic number.

81739550 is a deficient number, since it is larger than the sum of its proper divisors (70296106).

81739550 is a wasteful number, since it uses less digits than its factorization.

81739550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1634803 (or 1634798 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 81739550 is about 9040.9927552233. The cubic root of 81739550 is about 433.9876931676.

The spelling of 81739550 in words is "eighty-one million, seven hundred thirty-nine thousand, five hundred fifty".