21506567610 has 64 divisors (see below), whose sum is σ = 56430120960. Its totient is φ = 5202415680.

The previous prime is 21506567573. The next prime is 21506567623. The reversal of 21506567610 is 1676560512.

It is a super-2 number, since 2×21506567610² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82411 + ... + 223169.

It is an arithmetic number, because the mean of its divisors is an integer number (881720640).

Almost surely, 2^21506567610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21506567610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28215060480).

21506567610 is an abundant number, since it is smaller than the sum of its proper divisors (34923553350).

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

21506567610 is a wasteful number, since it uses less digits than its factorization.

21506567610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141243.

The product of its (nonzero) digits is 75600, while the sum is 39.

The spelling of 21506567610 in words is "twenty-one billion, five hundred six million, five hundred sixty-seven thousand, six hundred ten".