251516020 has 144 divisors (see below), whose sum is σ = 672924672. Its totient is φ = 78382080.

The previous prime is 251515991. The next prime is 251516029. The reversal of 251516020 is 20615152.

It is a junction number, because it is equal to n+sod(n) for n = 251515982 and 251516000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251516029) 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, 516217 + ... + 516703.

It is an arithmetic number, because the mean of its divisors is an integer number (4673088).

Almost surely, 2^251516020 is an apocalyptic number.

251516020 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 251516020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (336462336).

251516020 is an abundant number, since it is smaller than the sum of its proper divisors (421408652).

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

251516020 is a wasteful number, since it uses less digits than its factorization.

251516020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558 (or 549 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 251516020 is about 15859.2566030063. The cubic root of 251516020 is about 631.2313366374.

The spelling of 251516020 in words is "two hundred fifty-one million, five hundred sixteen thousand, twenty".