251606129 has 2 divisors, whose sum is σ = 251606130. Its totient is φ = 251606128.

The previous prime is 251606111. The next prime is 251606143. The reversal of 251606129 is 921606152.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 223801600 + 27804529 = 14960^2 + 5273^2 .

It is a cyclic number.

It is not a de Polignac number, because 251606129 - 2¹⁶ = 251540593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 251606095 and 251606104.

It is not a weakly prime, because it can be changed into another prime (251606429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125803064 + 125803065.

It is an arithmetic number, because the mean of its divisors is an integer number (125803065).

Almost surely, 2^251606129 is an apocalyptic number.

It is an amenable number.

251606129 is a deficient number, since it is larger than the sum of its proper divisors (1).

251606129 is an equidigital number, since it uses as much as digits as its factorization.

251606129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 251606129 is about 15862.0972446899. The cubic root of 251606129 is about 631.3067100115.

The spelling of 251606129 in words is "two hundred fifty-one million, six hundred six thousand, one hundred twenty-nine".