81457020 has 36 divisors (see below), whose sum is σ = 247086840. Its totient is φ = 21721824.

The previous prime is 81457003. The next prime is 81457039. The reversal of 81457020 is 2075418.

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

It is a super-2 number, since 2×81457020² = 13270492214560800, 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 11 ways as a sum of consecutive naturals, for example, 226090 + ... + 226449.

Almost surely, 2^81457020 is an apocalyptic number.

It is an amenable number.

81457020 is an abundant number, since it is smaller than the sum of its proper divisors (165629820).

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

81457020 is a wasteful number, since it uses less digits than its factorization.

81457020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452554 (or 452549 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 81457020 is about 9025.3542866748. The cubic root of 81457020 is about 433.4870946777.

The spelling of 81457020 in words is "eighty-one million, four hundred fifty-seven thousand, twenty".