21813383872 has 28 divisors (see below), whose sum is σ = 49469639440. Its totient is φ = 9348592896.

The previous prime is 21813383863. The next prime is 21813383881. The reversal of 21813383872 is 27838331812.

It is an interprime number because it is at equal distance from previous prime (21813383863) and next prime (21813383881).

It is a tau number, because it is divible by the number of its divisors (28).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24344847 + ... + 24345742.

Almost surely, 2^21813383872 is an apocalyptic number.

It is an amenable number.

21813383872 is an abundant number, since it is smaller than the sum of its proper divisors (27656255568).

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

21813383872 is an equidigital number, since it uses as much as digits as its factorization.

21813383872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48690608 (or 48690598 counting only the distinct ones).

The product of its digits is 387072, while the sum is 46.

The spelling of 21813383872 in words is "twenty-one billion, eight hundred thirteen million, three hundred eighty-three thousand, eight hundred seventy-two".