251561033 has 2 divisors, whose sum is σ = 251561034. Its totient is φ = 251561032.

The previous prime is 251561029. The next prime is 251561041. The reversal of 251561033 is 330165152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 243765769 + 7795264 = 15613^2 + 2792^2 .

It is a cyclic number.

It is not a de Polignac number, because 251561033 - 2² = 251561029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 251560993 and 251561011.

It is not a weakly prime, because it can be changed into another prime (251563033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125780516 + 125780517.

It is an arithmetic number, because the mean of its divisors is an integer number (125780517).

Almost surely, 2^251561033 is an apocalyptic number.

It is an amenable number.

251561033 is a deficient number, since it is larger than the sum of its proper divisors (1).

251561033 is an equidigital number, since it uses as much as digits as its factorization.

251561033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2700, while the sum is 26.

The square root of 251561033 is about 15860.6756791758. The cubic root of 251561033 is about 631.2689908609.

The spelling of 251561033 in words is "two hundred fifty-one million, five hundred sixty-one thousand, thirty-three".