21461758164 has 384 divisors, whose sum is σ = 71097384960. Its totient is φ = 5437756800.

The previous prime is 21461758163. The next prime is 21461758177. The reversal of 21461758164 is 46185716412.

21461758164 is a `hidden beast` number, since 2 + 1 + 4 + 6 + 1 + 7 + 581 + 64 = 666.

Its product of digits (322560) is a multiple of the sum of its prime divisors (480).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461758163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 96240957 + ... + 96241179.

It is an arithmetic number, because the mean of its divisors is an integer number (185149440).

Almost surely, 2^21461758164 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 21461758164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35548692480).

21461758164 is an abundant number, since it is smaller than the sum of its proper divisors (49635626796).

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

21461758164 is a wasteful number, since it uses less digits than its factorization.

21461758164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488 (or 480 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The spelling of 21461758164 in words is "twenty-one billion, four hundred sixty-one million, seven hundred fifty-eight thousand, one hundred sixty-four".