1261668408 has 128 divisors (see below), whose sum is σ = 4235051520. Its totient is φ = 302492160.

The previous prime is 1261668341. The next prime is 1261668431. The reversal of 1261668408 is 8048661621.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 1261668408.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2235 + ... + 50282.

It is an arithmetic number, because the mean of its divisors is an integer number (33086340).

Almost surely, 2^1261668408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261668408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2117525760).

1261668408 is an abundant number, since it is smaller than the sum of its proper divisors (2973383112).

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

1261668408 is a wasteful number, since it uses less digits than its factorization.

1261668408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52557 (or 52553 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 42.

The square root of 1261668408 is about 35519.9719594484. The cubic root of 1261668408 is about 1080.5588123190.

The spelling of 1261668408 in words is "one billion, two hundred sixty-one million, six hundred sixty-eight thousand, four hundred eight".