1261367664 has 60 divisors (see below), whose sum is σ = 3291804936. Its totient is φ = 416205696.

The previous prime is 1261367659. The next prime is 1261367743. The reversal of 1261367664 is 4667631621.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 507994 + ... + 510470.

Almost surely, 2^1261367664 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 1261367664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1645902468).

1261367664 is an abundant number, since it is smaller than the sum of its proper divisors (2030437272).

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

1261367664 is a wasteful number, since it uses less digits than its factorization.

1261367664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2694 (or 2585 counting only the distinct ones).

The product of its digits is 217728, while the sum is 42.

The square root of 1261367664 is about 35515.7382578484. The cubic root of 1261367664 is about 1080.4729478658.

The spelling of 1261367664 in words is "one billion, two hundred sixty-one million, three hundred sixty-seven thousand, six hundred sixty-four".