1161431021 has 2 divisors, whose sum is σ = 1161431022. Its totient is φ = 1161431020.

The previous prime is 1161431009. The next prime is 1161431039. The reversal of 1161431021 is 1201341611.

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., 1002418921 + 159012100 = 31661^2 + 12610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1161431021 is a prime.

It is a super-2 number, since 2×1161431021² = 2697844033082204882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1161430984 and 1161431002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1161436021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580715510 + 580715511.

It is an arithmetic number, because the mean of its divisors is an integer number (580715511).

Almost surely, 2^1161431021 is an apocalyptic number.

It is an amenable number.

1161431021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161431021 is an equidigital number, since it uses as much as digits as its factorization.

1161431021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 1161431021 is about 34079.7743683845. The cubic root of 1161431021 is about 1051.1494656015.

Adding to 1161431021 its reverse (1201341611), we get a palindrome (2362772632).

The spelling of 1161431021 in words is "one billion, one hundred sixty-one million, four hundred thirty-one thousand, twenty-one".