21341531 has 2 divisors, whose sum is σ = 21341532. Its totient is φ = 21341530.

The previous prime is 21341527. The next prime is 21341533. The reversal of 21341531 is 13514312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21341531 - 2² = 21341527 is a prime.

It is a super-2 number, since 2×21341531² = 910921890847922, which contains 22 as substring.

Together with 21341533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21341533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10670765 + 10670766.

It is an arithmetic number, because the mean of its divisors is an integer number (10670766).

Almost surely, 2^21341531 is an apocalyptic number.

21341531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21341531 is an equidigital number, since it uses as much as digits as its factorization.

21341531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 20.

The square root of 21341531 is about 4619.6894917299. The cubic root of 21341531 is about 277.3800298447.

Adding to 21341531 its reverse (13514312), we get a palindrome (34855843).

The spelling of 21341531 in words is "twenty-one million, three hundred forty-one thousand, five hundred thirty-one".