661956340 has 48 divisors (see below), whose sum is σ = 1407974400. Its totient is φ = 261403520.

The previous prime is 661956271. The next prime is 661956391. The reversal of 661956340 is 43659166.

It is a junction number, because it is equal to n+sod(n) for n = 661956293 and 661956302.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 568599 + ... + 569761.

It is an arithmetic number, because the mean of its divisors is an integer number (29332800).

Almost surely, 2^661956340 is an apocalyptic number.

It is an amenable number.

661956340 is an abundant number, since it is smaller than the sum of its proper divisors (746018060).

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

661956340 is a wasteful number, since it uses less digits than its factorization.

661956340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1512 (or 1510 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 40.

The square root of 661956340 is about 25728.5121995035. The cubic root of 661956340 is about 871.5181753756.

The spelling of 661956340 in words is "six hundred sixty-one million, nine hundred fifty-six thousand, three hundred forty".