661239937 has 4 divisors (see below), whose sum is σ = 661291456. Its totient is φ = 661188420.

The previous prime is 661239911. The next prime is 661239947. The reversal of 661239937 is 739932166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661239937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661239907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10612 + ... + 37882.

It is an arithmetic number, because the mean of its divisors is an integer number (165322864).

Almost surely, 2^661239937 is an apocalyptic number.

It is an amenable number.

661239937 is a deficient number, since it is larger than the sum of its proper divisors (51519).

661239937 is a wasteful number, since it uses less digits than its factorization.

661239937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51518.

The product of its digits is 367416, while the sum is 46.

The square root of 661239937 is about 25714.5860748331. The cubic root of 661239937 is about 871.2036613759.

The spelling of 661239937 in words is "six hundred sixty-one million, two hundred thirty-nine thousand, nine hundred thirty-seven".