21356374521 has 8 divisors (see below), whose sum is σ = 28485934144. Its totient is φ = 14232198960.

The previous prime is 21356374519. The next prime is 21356374591. The reversal of 21356374521 is 12547365312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21356374521 - 2¹ = 21356374519 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21356374521.

It is not an unprimeable number, because it can be changed into a prime (21356374591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1336750 + ... + 1352631.

It is an arithmetic number, because the mean of its divisors is an integer number (3560741768).

Almost surely, 2^21356374521 is an apocalyptic number.

It is an amenable number.

21356374521 is a deficient number, since it is larger than the sum of its proper divisors (7129559623).

21356374521 is a wasteful number, since it uses less digits than its factorization.

21356374521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2692031.

The product of its digits is 151200, while the sum is 39.

The spelling of 21356374521 in words is "twenty-one billion, three hundred fifty-six million, three hundred seventy-four thousand, five hundred twenty-one".