1631331521 has 2 divisors, whose sum is σ = 1631331522. Its totient is φ = 1631331520.

The previous prime is 1631331503. The next prime is 1631331563. The reversal of 1631331521 is 1251331361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1189491121 + 441840400 = 34489^2 + 21020^2 .

It is a cyclic number.

It is not a de Polignac number, because 1631331521 - 2¹⁴ = 1631315137 is a prime.

It is a super-2 number, since 2×1631331521² = 5322485062816346882, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1631334521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815665760 + 815665761.

It is an arithmetic number, because the mean of its divisors is an integer number (815665761).

Almost surely, 2^1631331521 is an apocalyptic number.

It is an amenable number.

1631331521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1631331521 is an equidigital number, since it uses as much as digits as its factorization.

1631331521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620, while the sum is 26.

The square root of 1631331521 is about 40389.7452455447. The cubic root of 1631331521 is about 1177.1922906476.

Adding to 1631331521 its reverse (1251331361), we get a palindrome (2882662882).

The spelling of 1631331521 in words is "one billion, six hundred thirty-one million, three hundred thirty-one thousand, five hundred twenty-one".