21320403131 has 2 divisors, whose sum is σ = 21320403132. Its totient is φ = 21320403130.

The previous prime is 21320403073. The next prime is 21320403149. The reversal of 21320403131 is 13130402312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21320403131 is a prime.

It is a super-2 number, since 2×21320403131² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21320403151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660201565 + 10660201566.

It is an arithmetic number, because the mean of its divisors is an integer number (10660201566).

Almost surely, 2^21320403131 is an apocalyptic number.

21320403131 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320403131 is an equidigital number, since it uses as much as digits as its factorization.

21320403131 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21320403131 its reverse (13130402312), we get a palindrome (34450805443).

The spelling of 21320403131 in words is "twenty-one billion, three hundred twenty million, four hundred three thousand, one hundred thirty-one".