21231312007 has 2 divisors, whose sum is σ = 21231312008. Its totient is φ = 21231312006.

The previous prime is 21231311989. The next prime is 21231312017. The reversal of 21231312007 is 70021313212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21231312007 - 2⁷ = 21231311879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231312017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615656003 + 10615656004.

It is an arithmetic number, because the mean of its divisors is an integer number (10615656004).

Almost surely, 2^21231312007 is an apocalyptic number.

21231312007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231312007 is an equidigital number, since it uses as much as digits as its factorization.

21231312007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 22.

Adding to 21231312007 its reverse (70021313212), we get a palindrome (91252625219).

The spelling of 21231312007 in words is "twenty-one billion, two hundred thirty-one million, three hundred twelve thousand, seven".