666550251 has 24 divisors (see below), whose sum is σ = 1000248704. Its totient is φ = 427265280.

The previous prime is 666550249. The next prime is 666550253. The reversal of 666550251 is 152055666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (666550249) and next prime (666550253).

It is not a de Polignac number, because 666550251 - 2¹ = 666550249 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666550253) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36195 + ... + 51411.

Almost surely, 2^666550251 is an apocalyptic number.

666550251 is a deficient number, since it is larger than the sum of its proper divisors (333698453).

666550251 is a wasteful number, since it uses less digits than its factorization.

666550251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15411 (or 15408 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 666550251 is about 25817.6344965994. The cubic root of 666550251 is about 873.5296125501.

The spelling of 666550251 in words is "six hundred sixty-six million, five hundred fifty thousand, two hundred fifty-one".