661907273 has 2 divisors, whose sum is σ = 661907274. Its totient is φ = 661907272.

The previous prime is 661907263. The next prime is 661907347. The reversal of 661907273 is 372709166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 660901264 + 1006009 = 25708^2 + 1003^2 .

It is a cyclic number.

It is not a de Polignac number, because 661907273 - 2²⁶ = 594798409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661907273.

It is not a weakly prime, because it can be changed into another prime (661907263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330953636 + 330953637.

It is an arithmetic number, because the mean of its divisors is an integer number (330953637).

Almost surely, 2^661907273 is an apocalyptic number.

It is an amenable number.

661907273 is a deficient number, since it is larger than the sum of its proper divisors (1).

661907273 is an equidigital number, since it uses as much as digits as its factorization.

661907273 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 95256, while the sum is 41.

The square root of 661907273 is about 25727.5586288322. The cubic root of 661907273 is about 871.4966413074.

The spelling of 661907273 in words is "six hundred sixty-one million, nine hundred seven thousand, two hundred seventy-three".