251787061 has 2 divisors, whose sum is σ = 251787062. Its totient is φ = 251787060.

The previous prime is 251787013. The next prime is 251787073. The reversal of 251787061 is 160787152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 243172836 + 8614225 = 15594^2 + 2935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-251787061 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 251787061.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251787091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125893530 + 125893531.

It is an arithmetic number, because the mean of its divisors is an integer number (125893531).

Almost surely, 2^251787061 is an apocalyptic number.

It is an amenable number.

251787061 is a deficient number, since it is larger than the sum of its proper divisors (1).

251787061 is an equidigital number, since it uses as much as digits as its factorization.

251787061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23520, while the sum is 37.

The square root of 251787061 is about 15867.7995008760. The cubic root of 251787061 is about 631.4579996712.

Subtracting from 251787061 its reverse (160787152), we obtain a palindrome (90999909).

The spelling of 251787061 in words is "two hundred fifty-one million, seven hundred eighty-seven thousand, sixty-one".