21645167634 has 48 divisors (see below), whose sum is σ = 48537575424. Its totient is φ = 6964012800.

The previous prime is 21645167627. The next prime is 21645167641. The reversal of 21645167634 is 43676154612.

21645167634 is a `hidden beast` number, since 2 + 1 + 6 + 4 + 5 + 1 + 6 + 7 + 634 = 666.

It is an interprime number because it is at equal distance from previous prime (21645167627) and next prime (21645167641).

It is a super-2 number, since 2×21645167634² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21645167634.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 163074 + ... + 264354.

It is an arithmetic number, because the mean of its divisors is an integer number (1011199488).

Almost surely, 2^21645167634 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21645167634, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24268787712).

21645167634 is an abundant number, since it is smaller than the sum of its proper divisors (26892407790).

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

21645167634 is a wasteful number, since it uses less digits than its factorization.

21645167634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101703 (or 101700 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The spelling of 21645167634 in words is "twenty-one billion, six hundred forty-five million, one hundred sixty-seven thousand, six hundred thirty-four".