631142021 has 2 divisors, whose sum is σ = 631142022. Its totient is φ = 631142020.

The previous prime is 631141999. The next prime is 631142023. The reversal of 631142021 is 120241136.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630712996 + 429025 = 25114^2 + 655^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-631142021 is a prime.

It is a Sophie Germain prime.

Together with 631142023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 631141984 and 631142002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631142023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315571010 + 315571011.

It is an arithmetic number, because the mean of its divisors is an integer number (315571011).

Almost surely, 2^631142021 is an apocalyptic number.

It is an amenable number.

631142021 is a deficient number, since it is larger than the sum of its proper divisors (1).

631142021 is an equidigital number, since it uses as much as digits as its factorization.

631142021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 631142021 is about 25122.5400984853. The cubic root of 631142021 is about 857.7795708305.

Adding to 631142021 its reverse (120241136), we get a palindrome (751383157).

The spelling of 631142021 in words is "six hundred thirty-one million, one hundred forty-two thousand, twenty-one".