21232421215 has 4 divisors (see below), whose sum is σ = 25478905464. Its totient is φ = 16985936968.

The previous prime is 21232421123. The next prime is 21232421237. The reversal of 21232421215 is 51212423212.

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 21232421215 - 2⁷ = 21232421087 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 21232421215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2123242117 + ... + 2123242126.

It is an arithmetic number, because the mean of its divisors is an integer number (6369726366).

Almost surely, 2^21232421215 is an apocalyptic number.

21232421215 is a deficient number, since it is larger than the sum of its proper divisors (4246484249).

21232421215 is an equidigital number, since it uses as much as digits as its factorization.

21232421215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4246484248.

The product of its digits is 1920, while the sum is 25.

Adding to 21232421215 its reverse (51212423212), we get a palindrome (72444844427).

The spelling of 21232421215 in words is "twenty-one billion, two hundred thirty-two million, four hundred twenty-one thousand, two hundred fifteen".