21965428751 has 4 divisors (see below), whose sum is σ = 25103347152. Its totient is φ = 18827510352.

The previous prime is 21965428747. The next prime is 21965428753. The reversal of 21965428751 is 15782456912.

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

It is not a de Polignac number, because 21965428751 - 2² = 21965428747 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 21965428751.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21965428753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1568959190 + ... + 1568959203.

It is an arithmetic number, because the mean of its divisors is an integer number (6275836788).

Almost surely, 2^21965428751 is an apocalyptic number.

21965428751 is a deficient number, since it is larger than the sum of its proper divisors (3137918401).

21965428751 is an equidigital number, since it uses as much as digits as its factorization.

21965428751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3137918400.

The product of its digits is 1209600, while the sum is 50.

The spelling of 21965428751 in words is "twenty-one billion, nine hundred sixty-five million, four hundred twenty-eight thousand, seven hundred fifty-one".