661207679 has 4 divisors (see below), whose sum is σ = 721317480. Its totient is φ = 601097880.

The previous prime is 661207663. The next prime is 661207691. The reversal of 661207679 is 976702166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661207679 - 2⁴ = 661207663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661207879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30054884 + ... + 30054905.

It is an arithmetic number, because the mean of its divisors is an integer number (180329370).

Almost surely, 2^661207679 is an apocalyptic number.

661207679 is a deficient number, since it is larger than the sum of its proper divisors (60109801).

661207679 is a wasteful number, since it uses less digits than its factorization.

661207679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60109800.

The product of its (nonzero) digits is 190512, while the sum is 44.

The square root of 661207679 is about 25713.9588356208. The cubic root of 661207679 is about 871.1894941813.

The spelling of 661207679 in words is "six hundred sixty-one million, two hundred seven thousand, six hundred seventy-nine".