21222154651 has 4 divisors (see below), whose sum is σ = 21490789600. Its totient is φ = 20953519704.

The previous prime is 21222154637. The next prime is 21222154669. The reversal of 21222154651 is 15645122212.

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 21222154651 - 2⁵ = 21222154619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222154601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134317356 + ... + 134317513.

It is an arithmetic number, because the mean of its divisors is an integer number (5372697400).

Almost surely, 2^21222154651 is an apocalyptic number.

21222154651 is a deficient number, since it is larger than the sum of its proper divisors (268634949).

21222154651 is an equidigital number, since it uses as much as digits as its factorization.

21222154651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268634948.

The product of its digits is 9600, while the sum is 31.

Adding to 21222154651 its reverse (15645122212), we get a palindrome (36867276863).

The spelling of 21222154651 in words is "twenty-one billion, two hundred twenty-two million, one hundred fifty-four thousand, six hundred fifty-one".