1256431121 has 16 divisors (see below), whose sum is σ = 1453800960. Its totient is φ = 1073153280.

The previous prime is 1256431073. The next prime is 1256431157. The reversal of 1256431121 is 1211346521.

It is a cyclic number.

It is not a de Polignac number, because 1256431121 - 2¹⁴ = 1256414737 is a prime.

It is a super-3 number, since 3×1256431121³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256431181) 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, 107975 + ... + 119043.

It is an arithmetic number, because the mean of its divisors is an integer number (90862560).

Almost surely, 2^1256431121 is an apocalyptic number.

1256431121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1256431121 is a deficient number, since it is larger than the sum of its proper divisors (197369839).

1256431121 is a wasteful number, since it uses less digits than its factorization.

1256431121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11704.

The product of its digits is 1440, while the sum is 26.

The square root of 1256431121 is about 35446.1721628725. The cubic root of 1256431121 is about 1079.0615765196.

Adding to 1256431121 its reverse (1211346521), we get a palindrome (2467777642).

The spelling of 1256431121 in words is "one billion, two hundred fifty-six million, four hundred thirty-one thousand, one hundred twenty-one".