21464640777 has 16 divisors (see below), whose sum is σ = 30027046400. Its totient is φ = 13621132800.

The previous prime is 21464640767. The next prime is 21464640781. The reversal of 21464640777 is 77704646412.

It is not a de Polignac number, because 21464640777 - 2⁷ = 21464640649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21464640767) 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 15 ways as a sum of consecutive naturals, for example, 1886152 + ... + 1897497.

It is an arithmetic number, because the mean of its divisors is an integer number (1876690400).

Almost surely, 2^21464640777 is an apocalyptic number.

It is an amenable number.

21464640777 is a deficient number, since it is larger than the sum of its proper divisors (8562405623).

21464640777 is a wasteful number, since it uses less digits than its factorization.

21464640777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3783744.

The product of its (nonzero) digits is 1580544, while the sum is 48.

The spelling of 21464640777 in words is "twenty-one billion, four hundred sixty-four million, six hundred forty thousand, seven hundred seventy-seven".