251221420455 has 16 divisors (see below), whose sum is σ = 425598642144. Its totient is φ = 126103301120.

The previous prime is 251221420427. The next prime is 251221420481. The reversal of 251221420455 is 554024122152.

It is not a de Polignac number, because 251221420455 - 2⁵ = 251221420423 is a prime.

It is a super-2 number, since 2×251221420455² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

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, 492590766 + ... + 492591275.

It is an arithmetic number, because the mean of its divisors is an integer number (26599915134).

Almost surely, 2^251221420455 is an apocalyptic number.

251221420455 is a deficient number, since it is larger than the sum of its proper divisors (174377221689).

251221420455 is a wasteful number, since it uses less digits than its factorization.

251221420455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985182066.

The product of its (nonzero) digits is 32000, while the sum is 33.

The spelling of 251221420455 in words is "two hundred fifty-one billion, two hundred twenty-one million, four hundred twenty thousand, four hundred fifty-five".