661380624 has 60 divisors (see below), whose sum is σ = 1900988076. Its totient is φ = 214500096.

The previous prime is 661380611. The next prime is 661380659. The reversal of 661380624 is 426083166.

It can be written as a sum of positive squares in 2 ways, for example, as 460875024 + 200505600 = 21468^2 + 14160^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56739 + ... + 67394.

Almost surely, 2^661380624 is an apocalyptic number.

It is an amenable number.

661380624 is an abundant number, since it is smaller than the sum of its proper divisors (1239607452).

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

661380624 is a wasteful number, since it uses less digits than its factorization.

661380624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124184 (or 124175 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 661380624 is about 25717.3214779456. The cubic root of 661380624 is about 871.2654434569.

The spelling of 661380624 in words is "six hundred sixty-one million, three hundred eighty thousand, six hundred twenty-four".