21317168016 has 105 divisors (see below), whose sum is σ = 62370211579. Its totient is φ = 6796778208.

The previous prime is 21317167997. The next prime is 21317168017. The reversal of 21317168016 is 61086171312.

The square root of 21317168016 is 146004.

It is a perfect power (a square), and thus also a powerful number.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21317168017) 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 20 ways as a sum of consecutive naturals, for example, 926833381 + ... + 926833403.

Almost surely, 2^21317168016 is an apocalyptic number.

21317168016 is the 146004-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21317168016

21317168016 is an abundant number, since it is smaller than the sum of its proper divisors (41053043563).

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

21317168016 is an frugal number, since it uses more digits than its factorization.

21317168016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

Multiplying 21317168016 by its sum of digits (36), we get a square (767418048576 = 876024²).

21317168016 divided by its sum of digits (36) gives a square (592143556 = 24334²).

The spelling of 21317168016 in words is "twenty-one billion, three hundred seventeen million, one hundred sixty-eight thousand, sixteen".