1261642445 has 24 divisors (see below), whose sum is σ = 1763506584. Its totient is φ = 863968896.

The previous prime is 1261642441. The next prime is 1261642493. The reversal of 1261642445 is 5442461621.

It can be written as a sum of positive squares in 4 ways, for example, as 15976009 + 1245666436 = 3997^2 + 35294^2 .

It is not a de Polignac number, because 1261642445 - 2² = 1261642441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261642441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 205967 + ... + 212003.

It is an arithmetic number, because the mean of its divisors is an integer number (73479441).

Almost surely, 2^1261642445 is an apocalyptic number.

It is an amenable number.

1261642445 is a deficient number, since it is larger than the sum of its proper divisors (501864139).

1261642445 is an equidigital number, since it uses as much as digits as its factorization.

1261642445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6909 (or 6902 counting only the distinct ones).

The product of its digits is 46080, while the sum is 35.

The square root of 1261642445 is about 35519.6064871220. The cubic root of 1261642445 is about 1080.5514002445.

The spelling of 1261642445 in words is "one billion, two hundred sixty-one million, six hundred forty-two thousand, four hundred forty-five".