251606066 has 4 divisors (see below), whose sum is σ = 377409102. Its totient is φ = 125803032.

The previous prime is 251606063. The next prime is 251606081. The reversal of 251606066 is 660606152.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 237006025 + 14600041 = 15395^2 + 3821^2 .

It is a super-2 number, since 2×251606066² = 126611224895992712, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (251606063) by changing a digit.

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 as a sum of consecutive naturals, namely, 62901515 + ... + 62901518.

Almost surely, 2^251606066 is an apocalyptic number.

251606066 is a deficient number, since it is larger than the sum of its proper divisors (125803036).

251606066 is a wasteful number, since it uses less digits than its factorization.

251606066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125803035.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 251606066 is about 15862.0952588238. The cubic root of 251606066 is about 631.3066573203.

The spelling of 251606066 in words is "two hundred fifty-one million, six hundred six thousand, sixty-six".