21309576484 has 27 divisors (see below), whose sum is σ = 43384370043. Its totient is φ = 9131799768.

The previous prime is 21309576481. The next prime is 21309576487. The reversal of 21309576484 is 48467590312.

It is a happy number.

The square root of 21309576484 is 145978.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (21309576481) and next prime (21309576487).

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (21309576481) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2038479 + ... + 2048905.

It is a 1-persistent number, because it is pandigital, but 2⋅21309576484 = 42619152968 is not.

Almost surely, 2^21309576484 is an apocalyptic number.

21309576484 is the 145978-th square number.

It is an amenable number.

21309576484 is an abundant number, since it is smaller than the sum of its proper divisors (22074793559).

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

21309576484 is an frugal number, since it uses more digits than its factorization.

21309576484 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20872 (or 10436 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 49.

Multiplying 21309576484 by its sum of digits (49), we get a square (1044169247716 = 1021846²).

21309576484 divided by its sum of digits (49) gives a square (434889316 = 20854²).

The spelling of 21309576484 in words is "twenty-one billion, three hundred nine million, five hundred seventy-six thousand, four hundred eighty-four".