251642220 has 48 divisors (see below), whose sum is σ = 705505248. Its totient is φ = 67018240.

The previous prime is 251642219. The next prime is 251642227. The reversal of 251642220 is 22246152.

251642220 = 5605² + 5606² + ... + 5612².

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (251642227) 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, 54232 + ... + 58688.

It is an arithmetic number, because the mean of its divisors is an integer number (14698026).

Almost surely, 2^251642220 is an apocalyptic number.

251642220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251642220 is an abundant number, since it is smaller than the sum of its proper divisors (453863028).

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

251642220 is a wasteful number, since it uses less digits than its factorization.

251642220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5410 (or 5408 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 251642220 is about 15863.2348529548. The cubic root of 251642220 is about 631.3368939624.

Adding to 251642220 its reverse (22246152), we get a palindrome (273888372).

The spelling of 251642220 in words is "two hundred fifty-one million, six hundred forty-two thousand, two hundred twenty".