21434531 has 2 divisors, whose sum is σ = 21434532. Its totient is φ = 21434530.

The previous prime is 21434471. The next prime is 21434579. The reversal of 21434531 is 13543412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21434531 - 2¹⁰ = 21433507 is a prime.

It is a super-2 number, since 2×21434531² = 918878238379922, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21434497 and 21434506.

It is not a weakly prime, because it can be changed into another prime (21434591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717265 + 10717266.

It is an arithmetic number, because the mean of its divisors is an integer number (10717266).

Almost surely, 2^21434531 is an apocalyptic number.

21434531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21434531 is an equidigital number, since it uses as much as digits as its factorization.

21434531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 23.

The square root of 21434531 is about 4629.7441613981. The cubic root of 21434531 is about 277.7823590296.

Adding to 21434531 its reverse (13543412), we get a palindrome (34977943).

The spelling of 21434531 in words is "twenty-one million, four hundred thirty-four thousand, five hundred thirty-one".