251240420511 has 24 divisors (see below), whose sum is σ = 373007771136. Its totient is φ = 162864732240.

The previous prime is 251240420507. The next prime is 251240420521. The reversal of 251240420511 is 115024042152.

It is a happy number.

251240420511 is a `hidden beast` number, since 2 + 5 + 124 + 0 + 4 + 20 + 511 = 666.

It is not a de Polignac number, because 251240420511 - 2² = 251240420507 is a prime.

It is a super-2 number, since 2×251240420511² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251240420521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1369305 + ... + 1541906.

It is an arithmetic number, because the mean of its divisors is an integer number (15541990464).

Almost surely, 2^251240420511 is an apocalyptic number.

251240420511 is a deficient number, since it is larger than the sum of its proper divisors (121767350625).

251240420511 is a wasteful number, since it uses less digits than its factorization.

251240420511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2911483 (or 2911480 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

Adding to 251240420511 its reverse (115024042152), we get a palindrome (366264462663).

The spelling of 251240420511 in words is "two hundred fifty-one billion, two hundred forty million, four hundred twenty thousand, five hundred eleven".