21261335344 has 30 divisors (see below), whose sum is σ = 41903981540. Its totient is φ = 10450459488.

The previous prime is 21261335323. The next prime is 21261335377. The reversal of 21261335344 is 44353316212.

It is a happy number.

It is a super-2 number, since 2×21261335344² (a number of 21 digits) contains 22 as substring.

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 5 ways as a sum of consecutive naturals, for example, 135174 + ... + 246565.

Almost surely, 2^21261335344 is an apocalyptic number.

It is an amenable number.

21261335344 is a deficient number, since it is larger than the sum of its proper divisors (20642646196).

21261335344 is an equidigital number, since it uses as much as digits as its factorization.

21261335344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381865 (or 381800 counting only the distinct ones).

The product of its digits is 51840, while the sum is 34.

The spelling of 21261335344 in words is "twenty-one billion, two hundred sixty-one million, three hundred thirty-five thousand, three hundred forty-four".