1298890865 has 16 divisors (see below), whose sum is σ = 1690612560. Its totient is φ = 954132480.

The previous prime is 1298890847. The next prime is 1298890867. The reversal of 1298890865 is 5680988921.

It can be written as a sum of positive squares in 8 ways, for example, as 137921536 + 1160969329 = 11744^2 + 34073^2 .

It is not a de Polignac number, because 1298890865 - 2¹⁴ = 1298874481 is a prime.

It is a super-4 number, since 4×1298890865⁴ (a number of 38 digits) contains 4444 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1298890865.

It is not an unprimeable number, because it can be changed into a prime (1298890867) 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, 182870 + ... + 189839.

It is an arithmetic number, because the mean of its divisors is an integer number (105663285).

Almost surely, 2^1298890865 is an apocalyptic number.

It is an amenable number.

1298890865 is a deficient number, since it is larger than the sum of its proper divisors (391721695).

1298890865 is a wasteful number, since it uses less digits than its factorization.

1298890865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372772.

The product of its (nonzero) digits is 2488320, while the sum is 56.

The square root of 1298890865 is about 36040.1285375066. The cubic root of 1298890865 is about 1091.0824096079.

The spelling of 1298890865 in words is "one billion, two hundred ninety-eight million, eight hundred ninety thousand, eight hundred sixty-five".