21466502551 has 4 divisors (see below), whose sum is σ = 23117771992. Its totient is φ = 19815233112.

The previous prime is 21466502539. The next prime is 21466502573. The reversal of 21466502551 is 15520566412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21466502551 - 2²⁷ = 21332284823 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21466502551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21466502591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 825634701 + ... + 825634726.

It is an arithmetic number, because the mean of its divisors is an integer number (5779442998).

Almost surely, 2^21466502551 is an apocalyptic number.

21466502551 is a deficient number, since it is larger than the sum of its proper divisors (1651269441).

21466502551 is a wasteful number, since it uses less digits than its factorization.

21466502551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1651269440.

The product of its (nonzero) digits is 72000, while the sum is 37.

The spelling of 21466502551 in words is "twenty-one billion, four hundred sixty-six million, five hundred two thousand, five hundred fifty-one".