1265988398 has 4 divisors (see below), whose sum is σ = 1898982600. Its totient is φ = 632994198.

The previous prime is 1265988397. The next prime is 1265988401. The reversal of 1265988398 is 8938895621.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265988397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 316497098 + ... + 316497101.

It is an arithmetic number, because the mean of its divisors is an integer number (474745650).

Almost surely, 2^1265988398 is an apocalyptic number.

1265988398 is a deficient number, since it is larger than the sum of its proper divisors (632994202).

1265988398 is an equidigital number, since it uses as much as digits as its factorization.

1265988398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632994201.

The product of its digits is 7464960, while the sum is 59.

The square root of 1265988398 is about 35580.7307120020. The cubic root of 1265988398 is about 1081.7906958451.

The spelling of 1265988398 in words is "one billion, two hundred sixty-five million, nine hundred eighty-eight thousand, three hundred ninety-eight".