661037131 has 2 divisors, whose sum is σ = 661037132. Its totient is φ = 661037130.

The previous prime is 661037101. The next prime is 661037173. The reversal of 661037131 is 131730166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661037131 is a prime.

It is a super-2 number, since 2×661037131² = 873940177121422322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661037131.

It is not a weakly prime, because it can be changed into another prime (661037101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330518565 + 330518566.

It is an arithmetic number, because the mean of its divisors is an integer number (330518566).

Almost surely, 2^661037131 is an apocalyptic number.

661037131 is a deficient number, since it is larger than the sum of its proper divisors (1).

661037131 is an equidigital number, since it uses as much as digits as its factorization.

661037131 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 661037131 is about 25710.6423684824. The cubic root of 661037131 is about 871.1145845843.

Adding to 661037131 its reverse (131730166), we get a palindrome (792767297).

The spelling of 661037131 in words is "six hundred sixty-one million, thirty-seven thousand, one hundred thirty-one".