1261973637376 has 81 divisors (see below), whose sum is σ = 2563216981689. Its totient is φ = 620103552000.

The previous prime is 1261973637359. The next prime is 1261973637517. The reversal of 1261973637376 is 6737363791621.

The square root of 1261973637376 is 1123376.

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., 41037035776 + 1220936601600 = 202576^2 + 1104960^2 .

It is a super-2 number, since 2×1261973637376² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a Duffinian number.

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, 1096414401 + ... + 1096415551.

Almost surely, 2^{1261973637376} is an apocalyptic number.

1261973637376 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

1261973637376 is the 1123376-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261973637376

1261973637376 is an abundant number, since it is smaller than the sum of its proper divisors (1301243344313).

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

1261973637376 is an frugal number, since it uses more digits than its factorization.

1261973637376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2440 (or 1214 counting only the distinct ones).

The product of its digits is 36006768, while the sum is 61.

The spelling of 1261973637376 in words is "one trillion, two hundred sixty-one billion, nine hundred seventy-three million, six hundred thirty-seven thousand, three hundred seventy-six".