1225806121 has 4 divisors (see below), whose sum is σ = 1226589952. Its totient is φ = 1225022292.

The previous prime is 1225806119. The next prime is 1225806139. The reversal of 1225806121 is 1216085221.

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: 1216085221 = 13 ⋅93545017.

It is a cyclic number.

It is not a de Polignac number, because 1225806121 - 2¹ = 1225806119 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 1225806121.

It is not an unprimeable number, because it can be changed into a prime (1225806221) 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, 389565 + ... + 392698.

It is an arithmetic number, because the mean of its divisors is an integer number (306647488).

Almost surely, 2^1225806121 is an apocalyptic number.

It is an amenable number.

1225806121 is a deficient number, since it is larger than the sum of its proper divisors (783831).

1225806121 is an equidigital number, since it uses as much as digits as its factorization.

1225806121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783830.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 1225806121 is about 35011.5141203576. The cubic root of 1225806121 is about 1070.2221336934. Note that the first 3 decimals are identical.

The spelling of 1225806121 in words is "one billion, two hundred twenty-five million, eight hundred six thousand, one hundred twenty-one".