21301215431 has 4 divisors (see below), whose sum is σ = 21301762872. Its totient is φ = 21300667992.

The previous prime is 21301215421. The next prime is 21301215479. The reversal of 21301215431 is 13451210312.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21301215431 is a prime.

It is a super-2 number, since 2×21301215431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21301215397 and 21301215406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21301215421) 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, 210485 + ... + 294798.

It is an arithmetic number, because the mean of its divisors is an integer number (5325440718).

Almost surely, 2^21301215431 is an apocalyptic number.

21301215431 is a deficient number, since it is larger than the sum of its proper divisors (547441).

21301215431 is an equidigital number, since it uses as much as digits as its factorization.

21301215431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547440.

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 21301215431 its reverse (13451210312), we get a palindrome (34752425743).

The spelling of 21301215431 in words is "twenty-one billion, three hundred one million, two hundred fifteen thousand, four hundred thirty-one".