21213907522 has 8 divisors (see below), whose sum is σ = 31842765756. Its totient is φ = 10599652272.

The previous prime is 21213907511. The next prime is 21213907523. The reversal of 21213907522 is 22570931212.

It can be written as a sum of positive squares in 2 ways, for example, as 17699907681 + 3513999841 = 133041^2 + 59279^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21213907523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3647113 + ... + 3652924.

Almost surely, 2^21213907522 is an apocalyptic number.

21213907522 is a deficient number, since it is larger than the sum of its proper divisors (10628858234).

21213907522 is a wasteful number, since it uses less digits than its factorization.

21213907522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7301492.

The product of its (nonzero) digits is 15120, while the sum is 34.

The spelling of 21213907522 in words is "twenty-one billion, two hundred thirteen million, nine hundred seven thousand, five hundred twenty-two".