81402588 has 36 divisors (see below), whose sum is σ = 208845000. Its totient is φ = 26728416.

The previous prime is 81402571. The next prime is 81402641. The reversal of 81402588 is 88520418.

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 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, 14463 + ... + 19286.

It is an arithmetic number, because the mean of its divisors is an integer number (5801250).

Almost surely, 2^81402588 is an apocalyptic number.

It is an amenable number.

81402588 is an abundant number, since it is smaller than the sum of its proper divisors (127442412).

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

81402588 is a wasteful number, since it uses less digits than its factorization.

81402588 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33826 (or 33821 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 81402588 is about 9022.3382778524. The cubic root of 81402588 is about 433.3905168455.

The spelling of 81402588 in words is "eighty-one million, four hundred two thousand, five hundred eighty-eight".