251221551145 has 8 divisors (see below), whose sum is σ = 302980766400. Its totient is φ = 199967304240.

The previous prime is 251221551137. The next prime is 251221551181. The reversal of 251221551145 is 541155122152.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 251221551145 - 2³ = 251221551137 is a prime.

It is a super-2 number, since 2×251221551145² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 251221551145.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126240991 + ... + 126242980.

It is an arithmetic number, because the mean of its divisors is an integer number (37872595800).

Almost surely, 2^251221551145 is an apocalyptic number.

It is an amenable number.

251221551145 is a deficient number, since it is larger than the sum of its proper divisors (51759215255).

251221551145 is a wasteful number, since it uses less digits than its factorization.

251221551145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252484175.

The product of its digits is 20000, while the sum is 34.

Adding to 251221551145 its reverse (541155122152), we get a palindrome (792376673297).

The spelling of 251221551145 in words is "two hundred fifty-one billion, two hundred twenty-one million, five hundred fifty-one thousand, one hundred forty-five".