21086136456 has 256 divisors, whose sum is σ = 69940869120. Its totient is φ = 5128704000.

The previous prime is 21086136433. The next prime is 21086136479. The reversal of 21086136456 is 65463168012.

It is an interprime number because it is at equal distance from previous prime (21086136433) and next prime (21086136479).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6627186 + ... + 6630366.

It is an arithmetic number, because the mean of its divisors is an integer number (273206520).

Almost surely, 2^21086136456 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 21086136456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34970434560).

21086136456 is an abundant number, since it is smaller than the sum of its proper divisors (48854732664).

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

21086136456 is a wasteful number, since it uses less digits than its factorization.

21086136456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3436 (or 3432 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 21086136456 in words is "twenty-one billion, eighty-six million, one hundred thirty-six thousand, four hundred fifty-six".