660437993 has 2 divisors, whose sum is σ = 660437994. Its totient is φ = 660437992.

The previous prime is 660437971. The next prime is 660438017. The reversal of 660437993 is 399734066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 505485289 + 154952704 = 22483^2 + 12448^2 .

It is a cyclic number.

It is not a de Polignac number, because 660437993 - 2²⁶ = 593329129 is a prime.

It is not a weakly prime, because it can be changed into another prime (660437933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330218996 + 330218997.

It is an arithmetic number, because the mean of its divisors is an integer number (330218997).

Almost surely, 2^660437993 is an apocalyptic number.

It is an amenable number.

660437993 is a deficient number, since it is larger than the sum of its proper divisors (1).

660437993 is an equidigital number, since it uses as much as digits as its factorization.

660437993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 47.

The square root of 660437993 is about 25698.9881707432. The cubic root of 660437993 is about 870.8513237240.

The spelling of 660437993 in words is "six hundred sixty million, four hundred thirty-seven thousand, nine hundred ninety-three".