21431243340646 has 64 divisors (see below), whose sum is σ = 33530289408000. Its totient is φ = 10266022166400.

The previous prime is 21431243340631. The next prime is 21431243340697. The reversal of 21431243340646 is 64604334213412.

It is a super-2 number, since 2×21431243340646² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 893663976 + ... + 893687956.

It is an arithmetic number, because the mean of its divisors is an integer number (523910772000).

Almost surely, 2^{21431243340646} is an apocalyptic number.

21431243340646 is a deficient number, since it is larger than the sum of its proper divisors (12099046067354).

21431243340646 is a wasteful number, since it uses less digits than its factorization.

21431243340646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24965.

The product of its (nonzero) digits is 995328, while the sum is 43.

The spelling of 21431243340646 in words is "twenty-one trillion, four hundred thirty-one billion, two hundred forty-three million, three hundred forty thousand, six hundred forty-six".