1251506361161 has 4 divisors (see below), whose sum is σ = 1430292984192. Its totient is φ = 1072719738132.

The previous prime is 1251506361143. The next prime is 1251506361211. The reversal of 1251506361161 is 1611636051521.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-1251506361161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251506361661) 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, 89393311505 + ... + 89393311518.

It is an arithmetic number, because the mean of its divisors is an integer number (357573246048).

Almost surely, 2^{1251506361161} is an apocalyptic number.

It is an amenable number.

1251506361161 is a deficient number, since it is larger than the sum of its proper divisors (178786623031).

1251506361161 is an equidigital number, since it uses as much as digits as its factorization.

1251506361161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178786623030.

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 1251506361161 in words is "one trillion, two hundred fifty-one billion, five hundred six million, three hundred sixty-one thousand, one hundred sixty-one".