21656041000 has 128 divisors (see below), whose sum is σ = 57686204160. Its totient is φ = 7532448000.

The previous prime is 21656040997. The next prime is 21656041003. The reversal of 21656041000 is 14065612.

It is an interprime number because it is at equal distance from previous prime (21656040997) and next prime (21656041003).

It is a super-2 number, since 2×21656041000² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21656041003) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 210202 + ... + 295798.

It is an arithmetic number, because the mean of its divisors is an integer number (450673470).

Almost surely, 2^21656041000 is an apocalyptic number.

21656041000 is a gapful number since it is divisible by the number (20) 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 21656041000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28843102080).

21656041000 is an abundant number, since it is smaller than the sum of its proper divisors (36030163160).

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

21656041000 is a wasteful number, since it uses less digits than its factorization.

21656041000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85652 (or 85638 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The spelling of 21656041000 in words is "twenty-one billion, six hundred fifty-six million, forty-one thousand".