666150021 has 16 divisors (see below), whose sum is σ = 990387520. Its totient is φ = 442525680.

The previous prime is 666149993. The next prime is 666150031. The reversal of 666150021 is 120051666.

It is a happy number.

It is not a de Polignac number, because 666150021 - 2¹³ = 666141829 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666150031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35950 + ... + 51231.

It is an arithmetic number, because the mean of its divisors is an integer number (61899220).

Almost surely, 2^666150021 is an apocalyptic number.

It is an amenable number.

666150021 is a deficient number, since it is larger than the sum of its proper divisors (324237499).

666150021 is a wasteful number, since it uses less digits than its factorization.

666150021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87473 (or 87467 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 666150021 is about 25809.8822352989. The cubic root of 666150021 is about 873.3547406358.

The spelling of 666150021 in words is "six hundred sixty-six million, one hundred fifty thousand, twenty-one".