81959004 has 36 divisors (see below), whose sum is σ = 209120184. Its totient is φ = 27063072.

The previous prime is 81958999. The next prime is 81959011. The reversal of 81959004 is 40095918.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 81959004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6787 + ... + 14490.

It is an arithmetic number, because the mean of its divisors is an integer number (5808894).

Almost surely, 2^81959004 is an apocalyptic number.

It is an amenable number.

81959004 is an abundant number, since it is smaller than the sum of its proper divisors (127161180).

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

81959004 is a wasteful number, since it uses less digits than its factorization.

81959004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21394 (or 21389 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 81959004 is about 9053.1212297196. The cubic root of 81959004 is about 434.3757355473.

The spelling of 81959004 in words is "eighty-one million, nine hundred fifty-nine thousand, four".