1561207266 has 24 divisors (see below), whose sum is σ = 3465120204. Its totient is φ = 507709440.

The previous prime is 1561207261. The next prime is 1561207279. The reversal of 1561207266 is 6627021651.

It is a happy number.

1561207266 is a `hidden beast` number, since 1 + 561 + 20 + 72 + 6 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1557486225 + 3721041 = 39465^2 + 1929^2 .

It is a super-2 number, since 2×1561207266² = 4874736254822389512, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1561207266.

It is not an unprimeable number, because it can be changed into a prime (1561207261) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1056991 + ... + 1058466.

Almost surely, 2^1561207266 is an apocalyptic number.

1561207266 is an abundant number, since it is smaller than the sum of its proper divisors (1903912938).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1561207266 is a wasteful number, since it uses less digits than its factorization.

1561207266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2115506 (or 2115503 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 1561207266 is about 39512.1154331175. The cubic root of 1561207266 is about 1160.0771019897.

The spelling of 1561207266 in words is "one billion, five hundred sixty-one million, two hundred seven thousand, two hundred sixty-six".