21242609431 has 2 divisors, whose sum is σ = 21242609432. Its totient is φ = 21242609430.

The previous prime is 21242609389. The next prime is 21242609441. The reversal of 21242609431 is 13490624212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21242609431 - 2⁷ = 21242609303 is a prime.

It is a super-2 number, since 2×21242609431² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21242609441) 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 as a sum of consecutive naturals, namely, 10621304715 + 10621304716.

It is an arithmetic number, because the mean of its divisors is an integer number (10621304716).

Almost surely, 2^21242609431 is an apocalyptic number.

21242609431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242609431 is an equidigital number, since it uses as much as digits as its factorization.

21242609431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 34.

The spelling of 21242609431 in words is "twenty-one billion, two hundred forty-two million, six hundred nine thousand, four hundred thirty-one".