661347764 has 36 divisors (see below), whose sum is σ = 1453879392. Its totient is φ = 257666640.

The previous prime is 661347761. The next prime is 661347767. The reversal of 661347764 is 467743166.

It is an interprime number because it is at equal distance from previous prime (661347761) and next prime (661347767).

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661347761) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94214 + ... + 100989.

Almost surely, 2^661347764 is an apocalyptic number.

It is an amenable number.

661347764 is an abundant number, since it is smaller than the sum of its proper divisors (792531628).

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

661347764 is a wasteful number, since it uses less digits than its factorization.

661347764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195236 (or 195223 counting only the distinct ones).

The product of its digits is 508032, while the sum is 44.

The square root of 661347764 is about 25716.6826009888. The cubic root of 661347764 is about 871.2510139158.

The spelling of 661347764 in words is "six hundred sixty-one million, three hundred forty-seven thousand, seven hundred sixty-four".