251649 has 6 divisors (see below), whose sum is σ = 363506. Its totient is φ = 167760.

The previous prime is 251639. The next prime is 251653. The reversal of 251649 is 946152.

251649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 186624 + 65025 = 432^2 + 255^2 .

It is not a de Polignac number, because 251649 - 2⁸ = 251393 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (251609) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13972 + ... + 13989.

2²⁵¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

251649 is a deficient number, since it is larger than the sum of its proper divisors (111857).

251649 is a wasteful number, since it uses less digits than its factorization.

251649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27967 (or 27964 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 251649 is about 501.6462897301. The cubic root of 251649 is about 63.1342563951.

It can be divided in two parts, 251 and 649, that added together give a square (900 = 30²).

The spelling of 251649 in words is "two hundred fifty-one thousand, six hundred forty-nine".