21646257401 has 8 divisors (see below), whose sum is σ = 22394491200. Its totient is φ = 20898144400.

The previous prime is 21646257389. The next prime is 21646257463. The reversal of 21646257401 is 10475264612.

It is a happy number.

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 21646257401 - 2²² = 21642063097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21646257901) 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 7 ways as a sum of consecutive naturals, for example, 481670 + ... + 524688.

It is an arithmetic number, because the mean of its divisors is an integer number (2799311400).

Almost surely, 2^21646257401 is an apocalyptic number.

It is an amenable number.

21646257401 is a deficient number, since it is larger than the sum of its proper divisors (748233799).

21646257401 is a wasteful number, since it uses less digits than its factorization.

21646257401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60399.

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 21646257401 in words is "twenty-one billion, six hundred forty-six million, two hundred fifty-seven thousand, four hundred one".