21416431 has 2 divisors, whose sum is σ = 21416432. Its totient is φ = 21416430.

The previous prime is 21416411. The next prime is 21416449. The reversal of 21416431 is 13461412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21416431 - 2¹⁹ = 20892143 is a prime.

It is a super-2 number, since 2×21416431² = 917327033555522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21416411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10708215 + 10708216.

It is an arithmetic number, because the mean of its divisors is an integer number (10708216).

Almost surely, 2^21416431 is an apocalyptic number.

21416431 is a deficient number, since it is larger than the sum of its proper divisors (1).

21416431 is an equidigital number, since it uses as much as digits as its factorization.

21416431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 22.

The square root of 21416431 is about 4627.7889969185. The cubic root of 21416431 is about 277.7041475899.

Adding to 21416431 its reverse (13461412), we get a palindrome (34877843).

The spelling of 21416431 in words is "twenty-one million, four hundred sixteen thousand, four hundred thirty-one".