1265993820 has 192 divisors, whose sum is σ = 4847754240. Its totient is φ = 267100416.

The previous prime is 1265993819. The next prime is 1265993837. The reversal of 1265993820 is 283995621.

1265993820 is a `hidden beast` number, since 1 + 2 + 6 + 599 + 38 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 36259 + ... + 62021.

It is an arithmetic number, because the mean of its divisors is an integer number (25248720).

Almost surely, 2^1265993820 is an apocalyptic number.

1265993820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1265993820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2423877120).

1265993820 is an abundant number, since it is smaller than the sum of its proper divisors (3581760420).

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

1265993820 is a wasteful number, since it uses less digits than its factorization.

1265993820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25801 (or 25793 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 1265993820 is about 35580.8069048469. The cubic root of 1265993820 is about 1081.7922402144.

The spelling of 1265993820 in words is "one billion, two hundred sixty-five million, nine hundred ninety-three thousand, eight hundred twenty".