81658368 has 200 divisors, whose sum is σ = 267371280. Its totient is φ = 24606720.

The previous prime is 81658351. The next prime is 81658387. The reversal of 81658368 is 86385618.

81658368 is a `hidden beast` number, since 8 + 1 + 6 + 583 + 68 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 456103 + ... + 456281.

Almost surely, 2^81658368 is an apocalyptic number.

81658368 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81658368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133685640).

81658368 is an abundant number, since it is smaller than the sum of its proper divisors (185712912).

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

81658368 is a wasteful number, since it uses less digits than its factorization.

81658368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 195 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The square root of 81658368 is about 9036.5019780886. The cubic root of 81658368 is about 433.8439697630.

The spelling of 81658368 in words is "eighty-one million, six hundred fifty-eight thousand, three hundred sixty-eight".