21779435915 has 16 divisors (see below), whose sum is σ = 26240572512. Its totient is φ = 17353499904.

The previous prime is 21779435851. The next prime is 21779435917. The reversal of 21779435915 is 51953497712.

It is a cyclic number.

It is not a de Polignac number, because 21779435915 - 2⁶ = 21779435851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21779435917) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1618997 + ... + 1632393.

It is an arithmetic number, because the mean of its divisors is an integer number (1640035782).

Almost surely, 2^21779435915 is an apocalyptic number.

21779435915 is a deficient number, since it is larger than the sum of its proper divisors (4461136597).

21779435915 is a wasteful number, since it uses less digits than its factorization.

21779435915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14686.

The product of its digits is 2381400, while the sum is 53.

The spelling of 21779435915 in words is "twenty-one billion, seven hundred seventy-nine million, four hundred thirty-five thousand, nine hundred fifteen".