661961726 has 4 divisors (see below), whose sum is σ = 992942592. Its totient is φ = 330980862.

The previous prime is 661961717. The next prime is 661961747. The reversal of 661961726 is 627169166.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165490430 + ... + 165490433.

It is an arithmetic number, because the mean of its divisors is an integer number (248235648).

Almost surely, 2^661961726 is an apocalyptic number.

661961726 is a deficient number, since it is larger than the sum of its proper divisors (330980866).

661961726 is a wasteful number, since it uses less digits than its factorization.

661961726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330980865.

The product of its digits is 163296, while the sum is 44.

The square root of 661961726 is about 25728.6168691595. The cubic root of 661961726 is about 871.5205390684.

The spelling of 661961726 in words is "six hundred sixty-one million, nine hundred sixty-one thousand, seven hundred twenty-six".