251221555222 has 32 divisors (see below), whose sum is σ = 429026160384. Its totient is φ = 109210754400.

The previous prime is 251221555219. The next prime is 251221555243. The reversal of 251221555222 is 222555122152.

It is a super-2 number, since 2×251221555222² (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, 3823653 + ... + 3888799.

It is an arithmetic number, because the mean of its divisors is an integer number (13407067512).

Almost surely, 2^251221555222 is an apocalyptic number.

251221555222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

251221555222 is a deficient number, since it is larger than the sum of its proper divisors (177804605162).

251221555222 is a wasteful number, since it uses less digits than its factorization.

251221555222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72804.

The product of its digits is 40000, while the sum is 34.

Adding to 251221555222 its reverse (222555122152), we get a palindrome (473776677374).

The spelling of 251221555222 in words is "two hundred fifty-one billion, two hundred twenty-one million, five hundred fifty-five thousand, two hundred twenty-two".