251721125 has 16 divisors (see below), whose sum is σ = 332630064. Its totient is φ = 189529600.

The previous prime is 251721121. The next prime is 251721133. The reversal of 251721125 is 521127152.

251721125 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 8 ways, for example, as 2365444 + 249355681 = 1538^2 + 15791^2 .

It is not a de Polignac number, because 251721125 - 2² = 251721121 is a prime.

It is a Duffinian number.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 251721094 and 251721103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251721121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57104 + ... + 61353.

It is an arithmetic number, because the mean of its divisors is an integer number (20789379).

Almost surely, 2^251721125 is an apocalyptic number.

251721125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

251721125 is a deficient number, since it is larger than the sum of its proper divisors (80908939).

251721125 is a wasteful number, since it uses less digits than its factorization.

251721125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118489 (or 118479 counting only the distinct ones).

The product of its digits is 1400, while the sum is 26.

The square root of 251721125 is about 15865.7216980508. The cubic root of 251721125 is about 631.4028744535.

Adding to 251721125 its reverse (521127152), we get a palindrome (772848277).

The spelling of 251721125 in words is "two hundred fifty-one million, seven hundred twenty-one thousand, one hundred twenty-five".