1251500405401 has 4 divisors (see below), whose sum is σ = 1251504179892. Its totient is φ = 1251496630912.

The previous prime is 1251500405359. The next prime is 1251500405473. The reversal of 1251500405401 is 1045040051521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 404621937801 + 846878467600 = 636099^2 + 920260^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251500405401 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1251500405401.

It is not an unprimeable number, because it can be changed into a prime (1251500408401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1336276 + ... + 2070901.

It is an arithmetic number, because the mean of its divisors is an integer number (312876044973).

Almost surely, 2^{1251500405401} is an apocalyptic number.

It is an amenable number.

1251500405401 is a deficient number, since it is larger than the sum of its proper divisors (3774491).

1251500405401 is an equidigital number, since it uses as much as digits as its factorization.

1251500405401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3774490.

The product of its (nonzero) digits is 4000, while the sum is 28.

Adding to 1251500405401 its reverse (1045040051521), we get a palindrome (2296540456922).

The spelling of 1251500405401 in words is "one trillion, two hundred fifty-one billion, five hundred million, four hundred five thousand, four hundred one".