21465581824 has 36 divisors (see below), whose sum is σ = 43549760380. Its totient is φ = 10556835840.

The previous prime is 21465581803. The next prime is 21465581861. The reversal of 21465581824 is 42818556412.

It can be written as a sum of positive squares in 2 ways, for example, as 1073741824 + 20391840000 = 32768^2 + 142800^2 .

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

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 3 ways as a sum of consecutive naturals, for example, 671679 + ... + 702910.

Almost surely, 2^21465581824 is an apocalyptic number.

It is an amenable number.

21465581824 is an abundant number, since it is smaller than the sum of its proper divisors (22084178556).

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

21465581824 is an equidigital number, since it uses as much as digits as its factorization.

21465581824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1374666 (or 1374652 counting only the distinct ones).

The product of its digits is 614400, while the sum is 46.

The spelling of 21465581824 in words is "twenty-one billion, four hundred sixty-five million, five hundred eighty-one thousand, eight hundred twenty-four".