661941774 has 64 divisors (see below), whose sum is σ = 1600630080. Its totient is φ = 201553920.

The previous prime is 661941773. The next prime is 661941823. The reversal of 661941774 is 477149166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661941773) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63234 + ... + 72954.

It is an arithmetic number, because the mean of its divisors is an integer number (25009845).

Almost surely, 2^661941774 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661941774, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (800315040).

661941774 is an abundant number, since it is smaller than the sum of its proper divisors (938688306).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661941774 is a wasteful number, since it uses less digits than its factorization.

661941774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9842 (or 9836 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 661941774 is about 25728.2291267782. The cubic root of 661941774 is about 871.5117828962.

The spelling of 661941774 in words is "six hundred sixty-one million, nine hundred forty-one thousand, seven hundred seventy-four".