251315220 has 192 divisors, whose sum is σ = 794787840. Its totient is φ = 58931712.

The previous prime is 251315213. The next prime is 251315231. The reversal of 251315220 is 22513152.

251315220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1978797 + ... + 1978923.

It is an arithmetic number, because the mean of its divisors is an integer number (4139520).

Almost surely, 2^251315220 is an apocalyptic number.

251315220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251315220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (397393920).

251315220 is an abundant number, since it is smaller than the sum of its proper divisors (543472620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251315220 is a wasteful number, since it uses less digits than its factorization.

251315220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 252 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 251315220 is about 15852.9246513065. The cubic root of 251315220 is about 631.0633089065.

Adding to 251315220 its reverse (22513152), we get a palindrome (273828372).

The spelling of 251315220 in words is "two hundred fifty-one million, three hundred fifteen thousand, two hundred twenty".