666251720 has 32 divisors (see below), whose sum is σ = 1577966400. Its totient is φ = 252474048.

The previous prime is 666251693. The next prime is 666251731. The reversal of 666251720 is 27152666.

666251720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 437564 + ... + 439083.

It is an arithmetic number, because the mean of its divisors is an integer number (49311450).

Almost surely, 2^666251720 is an apocalyptic number.

It is an amenable number.

666251720 is an abundant number, since it is smaller than the sum of its proper divisors (911714680).

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

666251720 is a wasteful number, since it uses less digits than its factorization.

666251720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 876677 (or 876673 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 666251720 is about 25811.8523163294. The cubic root of 666251720 is about 873.3991824689.

The spelling of 666251720 in words is "six hundred sixty-six million, two hundred fifty-one thousand, seven hundred twenty".