21354342431 has 2 divisors, whose sum is σ = 21354342432. Its totient is φ = 21354342430.

The previous prime is 21354342397. The next prime is 21354342509. The reversal of 21354342431 is 13424345312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21354342431 - 2¹⁸ = 21354080287 is a prime.

It is a super-2 number, since 2×21354342431² (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 (21354347431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677171215 + 10677171216.

It is an arithmetic number, because the mean of its divisors is an integer number (10677171216).

Almost surely, 2^21354342431 is an apocalyptic number.

21354342431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21354342431 is an equidigital number, since it uses as much as digits as its factorization.

21354342431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 32.

Adding to 21354342431 its reverse (13424345312), we get a palindrome (34778687743).

The spelling of 21354342431 in words is "twenty-one billion, three hundred fifty-four million, three hundred forty-two thousand, four hundred thirty-one".