81531954 has 32 divisors (see below), whose sum is σ = 207066240. Its totient is φ = 23294736.

The previous prime is 81531943. The next prime is 81532001. The reversal of 81531954 is 45913518.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107469 + ... + 108224.

It is an arithmetic number, because the mean of its divisors is an integer number (6470820).

Almost surely, 2^81531954 is an apocalyptic number.

81531954 is an abundant number, since it is smaller than the sum of its proper divisors (125534286).

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

81531954 is a wasteful number, since it uses less digits than its factorization.

81531954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215711 (or 215705 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 81531954 is about 9029.5046375756. The cubic root of 81531954 is about 433.6199785244.

The spelling of 81531954 in words is "eighty-one million, five hundred thirty-one thousand, nine hundred fifty-four".