21715779371 has 12 divisors (see below), whose sum is σ = 25705520736. Its totient is φ = 18223030320.

The previous prime is 21715779367. The next prime is 21715779419. The reversal of 21715779371 is 17397751712.

It is not a de Polignac number, because 21715779371 - 2² = 21715779367 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21715779271) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6901091 + ... + 6904236.

It is an arithmetic number, because the mean of its divisors is an integer number (2142126728).

Almost surely, 2^21715779371 is an apocalyptic number.

21715779371 is a deficient number, since it is larger than the sum of its proper divisors (3989741365).

21715779371 is a wasteful number, since it uses less digits than its factorization.

21715779371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13805362 (or 13805351 counting only the distinct ones).

The product of its digits is 648270, while the sum is 50.

The spelling of 21715779371 in words is "twenty-one billion, seven hundred fifteen million, seven hundred seventy-nine thousand, three hundred seventy-one".