81539492 has 12 divisors (see below), whose sum is σ = 142757580. Its totient is φ = 40751616.

The previous prime is 81539477. The next prime is 81539519. The reversal of 81539492 is 29493518.

It can be written as a sum of positive squares in 2 ways, for example, as 40271716 + 41267776 = 6346^2 + 6424^2 .

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14048 + ... + 18984.

It is an arithmetic number, because the mean of its divisors is an integer number (11896465).

Almost surely, 2^81539492 is an apocalyptic number.

It is an amenable number.

81539492 is a deficient number, since it is larger than the sum of its proper divisors (61218088).

81539492 is a wasteful number, since it uses less digits than its factorization.

81539492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9070 (or 9068 counting only the distinct ones).

The product of its digits is 77760, while the sum is 41.

The square root of 81539492 is about 9029.9220373157. The cubic root of 81539492 is about 433.6333414924.

The spelling of 81539492 in words is "eighty-one million, five hundred thirty-nine thousand, four hundred ninety-two".