1231625261 has 4 divisors (see below), whose sum is σ = 1233122592. Its totient is φ = 1230127932.

The previous prime is 1231625251. The next prime is 1231625287. The reversal of 1231625261 is 1625261321.

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 cyclic number.

It is not a de Polignac number, because 1231625261 - 2¹⁸ = 1231363117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231625251) 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, 747431 + ... + 749076.

It is an arithmetic number, because the mean of its divisors is an integer number (308280648).

Almost surely, 2^1231625261 is an apocalyptic number.

It is an amenable number.

1231625261 is a deficient number, since it is larger than the sum of its proper divisors (1497331).

1231625261 is an equidigital number, since it uses as much as digits as its factorization.

1231625261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1497330.

The product of its digits is 4320, while the sum is 29.

The square root of 1231625261 is about 35094.5189595185. The cubic root of 1231625261 is about 1071.9129784400.

Adding to 1231625261 its reverse (1625261321), we get a palindrome (2856886582).

The spelling of 1231625261 in words is "one billion, two hundred thirty-one million, six hundred twenty-five thousand, two hundred sixty-one".