21764907522 has 90 divisors (see below), whose sum is σ = 49796111673. Its totient is φ = 7105375728.

The previous prime is 21764907499. The next prime is 21764907539. The reversal of 21764907522 is 22570946712.

21764907522 is a `hidden beast` number, since 2 + 1 + 76 + 490 + 75 + 22 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17121984201 + 4642923321 = 130851^2 + 68139^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=104319.

It is a super-2 number, since 2×21764907522² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 125808628 + ... + 125808800.

Almost surely, 2^21764907522 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21764907522

21764907522 is an abundant number, since it is smaller than the sum of its proper divisors (28031204151).

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

21764907522 is an frugal number, since it uses more digits than its factorization.

21764907522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The spelling of 21764907522 in words is "twenty-one billion, seven hundred sixty-four million, nine hundred seven thousand, five hundred twenty-two".