1291877745664 has 99 divisors (see below), whose sum is σ = 2839488359421. Its totient is φ = 587035299840.

The previous prime is 1291877745647. The next prime is 1291877745671. The reversal of 1291877745664 is 4665477781921.

The square root of 1291877745664 is 1136608.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 388617585664 + 903260160000 = 623392^2 + 950400^2 .

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 1291877745664.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 400084402 + ... + 400087630.

Almost surely, 2^{1291877745664} is an apocalyptic number.

1291877745664 is the 1136608-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1291877745664

1291877745664 is an abundant number, since it is smaller than the sum of its proper divisors (1547610613757).

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

1291877745664 is an frugal number, since it uses more digits than its factorization.

1291877745664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6500 (or 3242 counting only the distinct ones).

The product of its digits is 142248960, while the sum is 67.

The spelling of 1291877745664 in words is "one trillion, two hundred ninety-one billion, eight hundred seventy-seven million, seven hundred forty-five thousand, six hundred sixty-four".