21162506904 has 384 divisors, whose sum is σ = 75740140800. Its totient is φ = 5412718080.

The previous prime is 21162506891. The next prime is 21162506909. The reversal of 21162506904 is 40960526112.

21162506904 is a `hidden beast` number, since 2 + 1 + 1 + 62 + 506 + 90 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21162506909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7799052 + ... + 7801764.

It is an arithmetic number, because the mean of its divisors is an integer number (197239950).

Almost surely, 2^21162506904 is an apocalyptic number.

21162506904 is a gapful number since it is divisible by the number (24) 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 21162506904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37870070400).

21162506904 is an abundant number, since it is smaller than the sum of its proper divisors (54577633896).

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

21162506904 is a wasteful number, since it uses less digits than its factorization.

21162506904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2820 (or 2803 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21162506904 in words is "twenty-one billion, one hundred sixty-two million, five hundred six thousand, nine hundred four".