251400261 has 16 divisors (see below), whose sum is σ = 383698944. Its totient is φ = 143427504.

The previous prime is 251400257. The next prime is 251400263. The reversal of 251400261 is 162004152.

It is not a de Polignac number, because 251400261 - 2² = 251400257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251400263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4336 + ... + 22838.

It is an arithmetic number, because the mean of its divisors is an integer number (23981184).

Almost surely, 2^251400261 is an apocalyptic number.

251400261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

251400261 is a deficient number, since it is larger than the sum of its proper divisors (132298683).

251400261 is a wasteful number, since it uses less digits than its factorization.

251400261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19160.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 251400261 is about 15855.6066109121. The cubic root of 251400261 is about 631.1344814135.

The spelling of 251400261 in words is "two hundred fifty-one million, four hundred thousand, two hundred sixty-one".