1125721637 has 4 divisors (see below), whose sum is σ = 1174666080. Its totient is φ = 1076777196.

The previous prime is 1125721603. The next prime is 1125721651. The reversal of 1125721637 is 7361275211.

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: 7361275211 = 1093 ⋅6734927.

It is a cyclic number.

It is not a de Polignac number, because 1125721637 - 2¹⁰ = 1125720613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1125721597 and 1125721606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1125721837) 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, 24472187 + ... + 24472232.

It is an arithmetic number, because the mean of its divisors is an integer number (293666520).

Almost surely, 2^1125721637 is an apocalyptic number.

It is an amenable number.

1125721637 is a deficient number, since it is larger than the sum of its proper divisors (48944443).

1125721637 is an equidigital number, since it uses as much as digits as its factorization.

1125721637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48944442.

The product of its digits is 17640, while the sum is 35.

The square root of 1125721637 is about 33551.7754671791. The cubic root of 1125721637 is about 1040.2642440606.

Adding to 1125721637 its reverse (7361275211), we get a palindrome (8486996848).

The spelling of 1125721637 in words is "one billion, one hundred twenty-five million, seven hundred twenty-one thousand, six hundred thirty-seven".