1261566451 has 8 divisors (see below), whose sum is σ = 1266502608. Its totient is φ = 1256640000.

The previous prime is 1261566443. The next prime is 1261566499. The reversal of 1261566451 is 1546651621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261566451 - 2³ = 1261566443 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 1261566451.

It is not an unprimeable number, because it can be changed into a prime (1261566401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351496 + ... + 355066.

It is an arithmetic number, because the mean of its divisors is an integer number (158312826).

Almost surely, 2^1261566451 is an apocalyptic number.

1261566451 is a deficient number, since it is larger than the sum of its proper divisors (4936157).

1261566451 is an equidigital number, since it uses as much as digits as its factorization.

1261566451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4853.

The product of its digits is 43200, while the sum is 37.

The square root of 1261566451 is about 35518.5367238010. The cubic root of 1261566451 is about 1080.5297044325.

The spelling of 1261566451 in words is "one billion, two hundred sixty-one million, five hundred sixty-six thousand, four hundred fifty-one".