21456616401 has 12 divisors (see below), whose sum is σ = 33810426000. Its totient is φ = 13004009880.

The previous prime is 21456616399. The next prime is 21456616429. The reversal of 21456616401 is 10461665412.

21456616401 is a `hidden beast` number, since 2 + 1 + 4 + 5 + 6 + 6 + 1 + 640 + 1 = 666.

It is not a de Polignac number, because 21456616401 - 2¹ = 21456616399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21456716401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108366651 + ... + 108366848.

It is an arithmetic number, because the mean of its divisors is an integer number (2817535500).

Almost surely, 2^21456616401 is an apocalyptic number.

It is an amenable number.

21456616401 is a deficient number, since it is larger than the sum of its proper divisors (12353809599).

21456616401 is a wasteful number, since it uses less digits than its factorization.

21456616401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216733516 (or 216733513 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21456616401 in words is "twenty-one billion, four hundred fifty-six million, six hundred sixteen thousand, four hundred one".