21456454665 has 16 divisors (see below), whose sum is σ = 34352107200. Its totient is φ = 11436182592.

The previous prime is 21456454661. The next prime is 21456454687. The reversal of 21456454665 is 56645465412.

It is a happy number.

It is not a de Polignac number, because 21456454665 - 2² = 21456454661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21456454661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 429270 + ... + 476639.

It is an arithmetic number, because the mean of its divisors is an integer number (2147006700).

Almost surely, 2^21456454665 is an apocalyptic number.

It is an amenable number.

21456454665 is a deficient number, since it is larger than the sum of its proper divisors (12895652535).

21456454665 is a wasteful number, since it uses less digits than its factorization.

21456454665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907496.

The product of its digits is 3456000, while the sum is 48.

The spelling of 21456454665 in words is "twenty-one billion, four hundred fifty-six million, four hundred fifty-four thousand, six hundred sixty-five".