251319985378561 has 16 divisors (see below), whose sum is σ = 277494201931968. Its totient is φ = 225700730424000.

The previous prime is 251319985378459. The next prime is 251319985378589. The reversal of 251319985378561 is 165873589913152.

It is a cyclic number.

It is not a de Polignac number, because 251319985378561 - 2⁴¹ = 249120962123009 is a prime.

It is a super-2 number, since 2×251319985378561² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251319985378591) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1079586 + ... + 22445611.

It is an arithmetic number, because the mean of its divisors is an integer number (17343387620748).

Almost surely, 2^{251319985378561} is an apocalyptic number.

It is an amenable number.

251319985378561 is a deficient number, since it is larger than the sum of its proper divisors (26174216553407).

251319985378561 is a wasteful number, since it uses less digits than its factorization.

251319985378561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23536992.

The product of its digits is 489888000, while the sum is 73.

The spelling of 251319985378561 in words is "two hundred fifty-one trillion, three hundred nineteen billion, nine hundred eighty-five million, three hundred seventy-eight thousand, five hundred sixty-one".