1265642028 has 36 divisors (see below), whose sum is σ = 3656299920. Its totient is φ = 361611936.

The previous prime is 1265642023. The next prime is 1265642047. The reversal of 1265642028 is 8202465621.

It is a happy number.

1265642028 is a `hidden beast` number, since 1 + 2 + 6 + 5 + 642 + 0 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1265641983 and 1265642001.

It is not an unprimeable number, because it can be changed into a prime (1265642023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2510943 + ... + 2511446.

Almost surely, 2^1265642028 is an apocalyptic number.

1265642028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1265642028 is an abundant number, since it is smaller than the sum of its proper divisors (2390657892).

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

1265642028 is a wasteful number, since it uses less digits than its factorization.

1265642028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5022406 (or 5022401 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 1265642028 is about 35575.8629972626. The cubic root of 1265642028 is about 1081.6920287954.

The spelling of 1265642028 in words is "one billion, two hundred sixty-five million, six hundred forty-two thousand, twenty-eight".