31423015021 has 2 divisors, whose sum is σ = 31423015022. Its totient is φ = 31423015020.

The previous prime is 31423015009. The next prime is 31423015079. The reversal of 31423015021 is 12051032413.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21330602500 + 10092412521 = 146050^2 + 100461^2 .

It is a cyclic number.

It is not a de Polignac number, because 31423015021 - 2⁷ = 31423014893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31423014983 and 31423015001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31423015121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15711507510 + 15711507511.

It is an arithmetic number, because the mean of its divisors is an integer number (15711507511).

Almost surely, 2^31423015021 is an apocalyptic number.

It is an amenable number.

31423015021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31423015021 is an equidigital number, since it uses as much as digits as its factorization.

31423015021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 31423015021 its reverse (12051032413), we get a palindrome (43474047434).

The spelling of 31423015021 in words is "thirty-one billion, four hundred twenty-three million, fifteen thousand, twenty-one".