81390396 has 24 divisors (see below), whose sum is σ = 190753920. Its totient is φ = 27009712.

The previous prime is 81390383. The next prime is 81390473. The reversal of 81390396 is 69309318.

It is a super-2 number, since 2×81390396² = 13248793122073632, which contains 22 as substring.

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, 12216 + ... + 17663.

It is an arithmetic number, because the mean of its divisors is an integer number (7948080).

Almost surely, 2^81390396 is an apocalyptic number.

It is an amenable number.

81390396 is an abundant number, since it is smaller than the sum of its proper divisors (109363524).

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

81390396 is a wasteful number, since it uses less digits than its factorization.

81390396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30113 (or 30111 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 81390396 is about 9021.6625962181. The cubic root of 81390396 is about 433.3688788725.

The spelling of 81390396 in words is "eighty-one million, three hundred ninety thousand, three hundred ninety-six".