1265398920 has 192 divisors, whose sum is σ = 4307696640. Its totient is φ = 321753600.

The previous prime is 1265398877. The next prime is 1265398987. The reversal of 1265398920 is 298935621.

1265398920 is a `hidden beast` number, since 1 + 26 + 539 + 8 + 92 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 791562 + ... + 793158.

It is an arithmetic number, because the mean of its divisors is an integer number (22435920).

Almost surely, 2^1265398920 is an apocalyptic number.

1265398920 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 1265398920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2153848320).

1265398920 is an abundant number, since it is smaller than the sum of its proper divisors (3042297720).

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

1265398920 is a wasteful number, since it uses less digits than its factorization.

1265398920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1716 (or 1709 counting only the distinct ones).

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

The square root of 1265398920 is about 35572.4460783905. The cubic root of 1265398920 is about 1081.6227662343.

The spelling of 1265398920 in words is "one billion, two hundred sixty-five million, three hundred ninety-eight thousand, nine hundred twenty".