1225687161 has 4 divisors (see below), whose sum is σ = 1634249552. Its totient is φ = 817124772.

The previous prime is 1225687153. The next prime is 1225687163. The reversal of 1225687161 is 1617865221.

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 not a de Polignac number, because 1225687161 - 2³ = 1225687153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1225687163) 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, 204281191 + ... + 204281196.

It is an arithmetic number, because the mean of its divisors is an integer number (408562388).

Almost surely, 2^1225687161 is an apocalyptic number.

It is an amenable number.

1225687161 is a deficient number, since it is larger than the sum of its proper divisors (408562391).

1225687161 is an equidigital number, since it uses as much as digits as its factorization.

1225687161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408562390.

The product of its digits is 40320, while the sum is 39.

The square root of 1225687161 is about 35009.8152094523. The cubic root of 1225687161 is about 1070.1875121924.

The spelling of 1225687161 in words is "one billion, two hundred twenty-five million, six hundred eighty-seven thousand, one hundred sixty-one".