1251213043 has 4 divisors (see below), whose sum is σ = 1258203240. Its totient is φ = 1244222848.

The previous prime is 1251213037. The next prime is 1251213079. The reversal of 1251213043 is 3403121521.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3403121521 = 19 ⋅179111659.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251213043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251213143) 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, 3494830 + ... + 3495187.

It is an arithmetic number, because the mean of its divisors is an integer number (314550810).

Almost surely, 2^1251213043 is an apocalyptic number.

1251213043 is a deficient number, since it is larger than the sum of its proper divisors (6990197).

1251213043 is an equidigital number, since it uses as much as digits as its factorization.

1251213043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6990196.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1251213043 is about 35372.4899180140. The cubic root of 1251213043 is about 1077.5656886147.

Adding to 1251213043 its reverse (3403121521), we get a palindrome (4654334564).

It can be divided in two parts, 125121 and 3043, that added together give a square (128164 = 358²).

The spelling of 1251213043 in words is "one billion, two hundred fifty-one million, two hundred thirteen thousand, forty-three".