1261149121 has 4 divisors (see below), whose sum is σ = 1266705072. Its totient is φ = 1255593172.

The previous prime is 1261149101. The next prime is 1261149137. The reversal of 1261149121 is 1219411621.

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 1261149121 - 2¹³ = 1261140929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1261149121.

It is not an unprimeable number, because it can be changed into a prime (1261149101) 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, 2777635 + ... + 2778088.

It is an arithmetic number, because the mean of its divisors is an integer number (316676268).

Almost surely, 2^1261149121 is an apocalyptic number.

It is an amenable number.

1261149121 is a deficient number, since it is larger than the sum of its proper divisors (5555951).

1261149121 is an equidigital number, since it uses as much as digits as its factorization.

1261149121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5555950.

The product of its digits is 864, while the sum is 28.

The square root of 1261149121 is about 35512.6614181478. The cubic root of 1261149121 is about 1080.4105437932.

The spelling of 1261149121 in words is "one billion, two hundred sixty-one million, one hundred forty-nine thousand, one hundred twenty-one".