21905156577 has 16 divisors (see below), whose sum is σ = 29582800640. Its totient is φ = 14415553152.

The previous prime is 21905156561. The next prime is 21905156587. The reversal of 21905156577 is 77565150912.

It is not a de Polignac number, because 21905156577 - 2⁴ = 21905156561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21905156527) 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, 1965573 + ... + 1976685.

It is an arithmetic number, because the mean of its divisors is an integer number (1848925040).

Almost surely, 2^21905156577 is an apocalyptic number.

It is an amenable number.

21905156577 is a deficient number, since it is larger than the sum of its proper divisors (7677644063).

21905156577 is a wasteful number, since it uses less digits than its factorization.

21905156577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19512.

The product of its (nonzero) digits is 661500, while the sum is 48.

The spelling of 21905156577 in words is "twenty-one billion, nine hundred five million, one hundred fifty-six thousand, five hundred seventy-seven".