21457320472 has 64 divisors (see below), whose sum is σ = 46979850240. Its totient is φ = 8997609600.

The previous prime is 21457320463. The next prime is 21457320503. The reversal of 21457320472 is 27402375412.

It is a super-2 number, since 2×21457320472² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 636013 + ... + 668899.

It is an arithmetic number, because the mean of its divisors is an integer number (734060160).

Almost surely, 2^21457320472 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 21457320472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23489925120).

21457320472 is an abundant number, since it is smaller than the sum of its proper divisors (25522529768).

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

21457320472 is a wasteful number, since it uses less digits than its factorization.

21457320472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33152 (or 33148 counting only the distinct ones).

The product of its (nonzero) digits is 94080, while the sum is 37.

Adding to 21457320472 its reverse (27402375412), we get a palindrome (48859695884).

The spelling of 21457320472 in words is "twenty-one billion, four hundred fifty-seven million, three hundred twenty thousand, four hundred seventy-two".