21217930704 has 60 divisors (see below), whose sum is σ = 59682241476. Its totient is φ = 7036732416.

The previous prime is 21217930703. The next prime is 21217930709. The reversal of 21217930704 is 40703971212.

It can be written as a sum of positive squares in 2 ways, for example, as 12310346304 + 8907584400 = 110952^2 + 94380^2 .

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 (21217930703) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 345609 + ... + 402344.

Almost surely, 2^21217930704 is an apocalyptic number.

21217930704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21217930704 is an abundant number, since it is smaller than the sum of its proper divisors (38464310772).

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

21217930704 is a wasteful number, since it uses less digits than its factorization.

21217930704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748164 (or 748155 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The spelling of 21217930704 in words is "twenty-one billion, two hundred seventeen million, nine hundred thirty thousand, seven hundred four".