81403056 has 140 divisors (see below), whose sum is σ = 270521872. Its totient is φ = 23234688.

The previous prime is 81403051. The next prime is 81403061. The reversal of 81403056 is 65030418.

It is an interprime number because it is at equal distance from previous prime (81403051) and next prime (81403061).

It is a super-2 number, since 2×81403056² = 13252915052278272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81403051) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 81150 + ... + 82146.

Almost surely, 2^81403056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81403056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135260936).

81403056 is an abundant number, since it is smaller than the sum of its proper divisors (189118816).

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

81403056 is an equidigital number, since it uses as much as digits as its factorization.

81403056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1030 (or 1009 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 81403056 is about 9022.3642134421. The cubic root of 81403056 is about 433.3913473939.

The spelling of 81403056 in words is "eighty-one million, four hundred three thousand, fifty-six".