251401005 has 48 divisors (see below), whose sum is σ = 449070336. Its totient is φ = 130032000.

The previous prime is 251401001. The next prime is 251401013. The reversal of 251401005 is 500104152.

It is not a de Polignac number, because 251401005 - 2² = 251401001 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251401001) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 334380 + ... + 335130.

It is an arithmetic number, because the mean of its divisors is an integer number (9355632).

Almost surely, 2^251401005 is an apocalyptic number.

It is an amenable number.

251401005 is a deficient number, since it is larger than the sum of its proper divisors (197669331).

251401005 is a wasteful number, since it uses less digits than its factorization.

251401005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978 (or 975 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 251401005 is about 15855.6300726272. The cubic root of 251401005 is about 631.1351040110.

Adding to 251401005 its reverse (500104152), we get a palindrome (751505157).

The spelling of 251401005 in words is "two hundred fifty-one million, four hundred one thousand, five".