1298778921 has 32 divisors (see below), whose sum is σ = 2155785600. Its totient is φ = 765858240.

The previous prime is 1298778907. The next prime is 1298778941.

1298778921 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1298778921 - 2⁶ = 1298778857 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1298778941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48106 + ... + 70083.

It is an arithmetic number, because the mean of its divisors is an integer number (67368300).

Almost surely, 2^1298778921 is an apocalyptic number.

1298778921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1298778921 is a deficient number, since it is larger than the sum of its proper divisors (857006679).

1298778921 is a wasteful number, since it uses less digits than its factorization.

1298778921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118246 (or 118240 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 1298778921 is about 36038.5754574178. The cubic root of 1298778921 is about 1091.0510639828.

The spelling of 1298778921 in words is "one billion, two hundred ninety-eight million, seven hundred seventy-eight thousand, nine hundred twenty-one".