661644967 has 2 divisors, whose sum is σ = 661644968. Its totient is φ = 661644966.

The previous prime is 661644959. The next prime is 661644983. The reversal of 661644967 is 769446166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661644967 - 2³ = 661644959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661644967.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661644937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330822483 + 330822484.

It is an arithmetic number, because the mean of its divisors is an integer number (330822484).

Almost surely, 2^661644967 is an apocalyptic number.

661644967 is a deficient number, since it is larger than the sum of its proper divisors (1).

661644967 is an equidigital number, since it uses as much as digits as its factorization.

661644967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 49.

The square root of 661644967 is about 25722.4603605487. The cubic root of 661644967 is about 871.3815048369.

The spelling of 661644967 in words is "six hundred sixty-one million, six hundred forty-four thousand, nine hundred sixty-seven".