21671193456 has 120 divisors (see below), whose sum is σ = 66237260544. Its totient is φ = 6559639680.

The previous prime is 21671193419. The next prime is 21671193493. The reversal of 21671193456 is 65439117612.

21671193456 is a `hidden beast` number, since 2 + 1 + 6 + 7 + 1 + 193 + 456 = 666.

It is an interprime number because it is at equal distance from previous prime (21671193419) and next prime (21671193493).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1492825 + ... + 1507271.

Almost surely, 2^21671193456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21671193456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33118630272).

21671193456 is an abundant number, since it is smaller than the sum of its proper divisors (44566067088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21671193456 is a wasteful number, since it uses less digits than its factorization.

21671193456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15419 (or 15410 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The spelling of 21671193456 in words is "twenty-one billion, six hundred seventy-one million, one hundred ninety-three thousand, four hundred fifty-six".