656519657421 has 8 divisors (see below), whose sum is σ = 875427174720. Its totient is φ = 437645955872.

The previous prime is 656519657393. The next prime is 656519657447. The reversal of 656519657421 is 124756915656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 656519657421 - 2⁹ = 656519656909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656519657461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8408601 + ... + 8486318.

It is an arithmetic number, because the mean of its divisors is an integer number (109428396840).

Almost surely, 2^656519657421 is an apocalyptic number.

It is an amenable number.

656519657421 is a deficient number, since it is larger than the sum of its proper divisors (218907517299).

656519657421 is a wasteful number, since it uses less digits than its factorization.

656519657421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16907875.

The product of its digits is 13608000, while the sum is 57.

The spelling of 656519657421 in words is "six hundred fifty-six billion, five hundred nineteen million, six hundred fifty-seven thousand, four hundred twenty-one".