21107751577 has 4 divisors (see below), whose sum is σ = 23026638096. Its totient is φ = 19188865060.

The previous prime is 21107751563. The next prime is 21107751589. The reversal of 21107751577 is 77515770112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21107751577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21107751557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 959443243 + ... + 959443264.

It is an arithmetic number, because the mean of its divisors is an integer number (5756659524).

Almost surely, 2^21107751577 is an apocalyptic number.

It is an amenable number.

21107751577 is a deficient number, since it is larger than the sum of its proper divisors (1918886519).

21107751577 is a wasteful number, since it uses less digits than its factorization.

21107751577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1918886518.

The product of its (nonzero) digits is 120050, while the sum is 43.

The spelling of 21107751577 in words is "twenty-one billion, one hundred seven million, seven hundred fifty-one thousand, five hundred seventy-seven".