21071581472 has 54 divisors (see below), whose sum is σ = 42223334643. Its totient is φ = 10351442112.

The previous prime is 21071581463. The next prime is 21071581493. The reversal of 21071581472 is 27418517012.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 10535790736 + 10535790736 = 102644^2 + 102644^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=102644.

It is a super-2 number, since 2×21071581472² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 55016993 + ... + 55017375.

Almost surely, 2^21071581472 is an apocalyptic number.

It is an amenable number.

21071581472 is an abundant number, since it is smaller than the sum of its proper divisors (21151753171).

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

21071581472 is an frugal number, since it uses more digits than its factorization.

21071581472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 38.

The spelling of 21071581472 in words is "twenty-one billion, seventy-one million, five hundred eighty-one thousand, four hundred seventy-two".