251421305420 has 12 divisors (see below), whose sum is σ = 527984741424. Its totient is φ = 100568522160.

The previous prime is 251421305393. The next prime is 251421305441. The reversal of 251421305420 is 24503124152.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6285532616 + ... + 6285532655.

It is an arithmetic number, because the mean of its divisors is an integer number (43998728452).

Almost surely, 2^251421305420 is an apocalyptic number.

251421305420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251421305420 is an abundant number, since it is smaller than the sum of its proper divisors (276563436004).

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

251421305420 is a wasteful number, since it uses less digits than its factorization.

251421305420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12571065280 (or 12571065278 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 251421305420 its reverse (24503124152), we get a palindrome (275924429572).

The spelling of 251421305420 in words is "two hundred fifty-one billion, four hundred twenty-one million, three hundred five thousand, four hundred twenty".