1225621081 has 4 divisors (see below), whose sum is σ = 1225757412. Its totient is φ = 1225484752.

The previous prime is 1225621063. The next prime is 1225621091. The reversal of 1225621081 is 1801265221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 470195856 + 755425225 = 21684^2 + 27485^2 .

It is a cyclic number.

It is not a de Polignac number, because 1225621081 - 2⁷ = 1225620953 is a prime.

It is a super-2 number, since 2×1225621081² = 3004294068383217122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1225621031) 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, 53650 + ... + 73003.

It is an arithmetic number, because the mean of its divisors is an integer number (306439353).

Almost surely, 2^1225621081 is an apocalyptic number.

It is an amenable number.

1225621081 is a deficient number, since it is larger than the sum of its proper divisors (136331).

1225621081 is an equidigital number, since it uses as much as digits as its factorization.

1225621081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136330.

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

The square root of 1225621081 is about 35008.8714613882. The cubic root of 1225621081 is about 1070.1682796443.

The spelling of 1225621081 in words is "one billion, two hundred twenty-five million, six hundred twenty-one thousand, eighty-one".