661258860 has 48 divisors (see below), whose sum is σ = 1960441056. Its totient is φ = 165962752.

The previous prime is 661258853. The next prime is 661258879. The reversal of 661258860 is 68852166.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 323127 + ... + 325166.

It is an arithmetic number, because the mean of its divisors is an integer number (40842522).

Almost surely, 2^661258860 is an apocalyptic number.

661258860 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661258860 is an abundant number, since it is smaller than the sum of its proper divisors (1299182196).

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

661258860 is a wasteful number, since it uses less digits than its factorization.

661258860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648322 (or 648320 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 661258860 is about 25714.9540151251. The cubic root of 661258860 is about 871.2119718387.

The spelling of 661258860 in words is "six hundred sixty-one million, two hundred fifty-eight thousand, eight hundred sixty".