1321787265 has 16 divisors (see below), whose sum is σ = 2121256896. Its totient is φ = 702820800.

The previous prime is 1321787219. The next prime is 1321787267. The reversal of 1321787265 is 5627871231.

It is not a de Polignac number, because 1321787265 - 2¹⁹ = 1321262977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1321787267) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128146 + ... + 138075.

It is an arithmetic number, because the mean of its divisors is an integer number (132578556).

Almost surely, 2^1321787265 is an apocalyptic number.

1321787265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1321787265 is a deficient number, since it is larger than the sum of its proper divisors (799469631).

1321787265 is a wasteful number, since it uses less digits than its factorization.

1321787265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266560.

The product of its digits is 141120, while the sum is 42.

The square root of 1321787265 is about 36356.3923540276. The cubic root of 1321787265 is about 1097.4561782549.

The spelling of 1321787265 in words is "one billion, three hundred twenty-one million, seven hundred eighty-seven thousand, two hundred sixty-five".