21457666572 has 24 divisors (see below), whose sum is σ = 50106527856. Its totient is φ = 7147035648.

The previous prime is 21457666523. The next prime is 21457666589. The reversal of 21457666572 is 27566675412.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 673773 + ... + 704900.

It is an arithmetic number, because the mean of its divisors is an integer number (2087771994).

Almost surely, 2^21457666572 is an apocalyptic number.

It is an amenable number.

21457666572 is an abundant number, since it is smaller than the sum of its proper divisors (28648861284).

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

21457666572 is a wasteful number, since it uses less digits than its factorization.

21457666572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1379977 (or 1379975 counting only the distinct ones).

The product of its digits is 4233600, while the sum is 51.

The spelling of 21457666572 in words is "twenty-one billion, four hundred fifty-seven million, six hundred sixty-six thousand, five hundred seventy-two".