81551742 has 16 divisors (see below), whose sum is σ = 163303680. Its totient is φ = 27150552.

The previous prime is 81551719. The next prime is 81551753. The reversal of 81551742 is 24715518.

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, 2758 + ... + 13065.

It is an arithmetic number, because the mean of its divisors is an integer number (10206480).

Almost surely, 2^81551742 is an apocalyptic number.

81551742 is an abundant number, since it is smaller than the sum of its proper divisors (81751938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81551742 is a wasteful number, since it uses less digits than its factorization.

81551742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16687.

The product of its digits is 11200, while the sum is 33.

The square root of 81551742 is about 9030.6003122716. The cubic root of 81551742 is about 433.6550558883.

The spelling of 81551742 in words is "eighty-one million, five hundred fifty-one thousand, seven hundred forty-two".