21320775420 has 96 divisors (see below), whose sum is σ = 72239827968. Its totient is φ = 4586652672.

The previous prime is 21320775409. The next prime is 21320775431. The reversal of 21320775420 is 2457702312.

It is an interprime number because it is at equal distance from previous prime (21320775409) and next prime (21320775431).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1485912 + ... + 1500191.

It is an arithmetic number, because the mean of its divisors is an integer number (752498208).

Almost surely, 2^21320775420 is an apocalyptic number.

21320775420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21320775420 is an abundant number, since it is smaller than the sum of its proper divisors (50919052548).

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

21320775420 is a wasteful number, since it uses less digits than its factorization.

21320775420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2986139 (or 2986137 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 33.

The spelling of 21320775420 in words is "twenty-one billion, three hundred twenty million, seven hundred seventy-five thousand, four hundred twenty".