251205420 has 48 divisors (see below), whose sum is σ = 704890368. Its totient is φ = 66843840.

The previous prime is 251205419. The next prime is 251205439. The reversal of 251205420 is 24502152.

It is a happy number.

It is a super-3 number, since 3×251205420³ (a number of 26 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25197 + ... + 33723.

It is an arithmetic number, because the mean of its divisors is an integer number (14685216).

Almost surely, 2^251205420 is an apocalyptic number.

251205420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251205420 is an abundant number, since it is smaller than the sum of its proper divisors (453684948).

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

251205420 is a wasteful number, since it uses less digits than its factorization.

251205420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9030 (or 9028 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 251205420 is about 15849.4611895799. The cubic root of 251205420 is about 630.9713913473.

Adding to 251205420 its reverse (24502152), we get a palindrome (275707572).

The spelling of 251205420 in words is "two hundred fifty-one million, two hundred five thousand, four hundred twenty".