21534031 has 2 divisors, whose sum is σ = 21534032. Its totient is φ = 21534030.

The previous prime is 21533999. The next prime is 21534041. The reversal of 21534031 is 13043512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21534031 - 2⁵ = 21533999 is a prime.

It is a super-2 number, since 2×21534031² = 927428982217922, 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 (21534041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767015 + 10767016.

It is an arithmetic number, because the mean of its divisors is an integer number (10767016).

Almost surely, 2^21534031 is an apocalyptic number.

21534031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21534031 is an equidigital number, since it uses as much as digits as its factorization.

21534031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21534031 is about 4640.4774538834. The cubic root of 21534031 is about 278.2115214717.

Adding to 21534031 its reverse (13043512), we get a palindrome (34577543).

The spelling of 21534031 in words is "twenty-one million, five hundred thirty-four thousand, thirty-one".