1251731461 has 4 divisors (see below), whose sum is σ = 1306154592. Its totient is φ = 1197308332.

The previous prime is 1251731447. The next prime is 1251731473. The reversal of 1251731461 is 1641371521.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1641371521 = 7549 ⋅217429.

It is not a de Polignac number, because 1251731461 - 2¹³ = 1251723269 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251731861) 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, 27211531 + ... + 27211576.

It is an arithmetic number, because the mean of its divisors is an integer number (326538648).

Almost surely, 2^1251731461 is an apocalyptic number.

It is an amenable number.

1251731461 is a deficient number, since it is larger than the sum of its proper divisors (54423131).

1251731461 is an equidigital number, since it uses as much as digits as its factorization.

1251731461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54423130.

The product of its digits is 5040, while the sum is 31.

The square root of 1251731461 is about 35379.8171419808. The cubic root of 1251731461 is about 1077.7144914950.

The spelling of 1251731461 in words is "one billion, two hundred fifty-one million, seven hundred thirty-one thousand, four hundred sixty-one".