1398768521 has 4 divisors (see below), whose sum is σ = 1411841232. Its totient is φ = 1385695812.

The previous prime is 1398768509. The next prime is 1398768541. The reversal of 1398768521 is 1258678931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1398768521 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1398768521.

It is not an unprimeable number, because it can be changed into a prime (1398768541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6536195 + ... + 6536408.

It is an arithmetic number, because the mean of its divisors is an integer number (352960308).

Almost surely, 2^1398768521 is an apocalyptic number.

It is an amenable number.

1398768521 is a deficient number, since it is larger than the sum of its proper divisors (13072711).

1398768521 is a wasteful number, since it uses less digits than its factorization.

1398768521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13072710.

The product of its digits is 725760, while the sum is 50.

The square root of 1398768521 is about 37400.1139169388. The cubic root of 1398768521 is about 1118.3608358732.

The spelling of 1398768521 in words is "one billion, three hundred ninety-eight million, seven hundred sixty-eight thousand, five hundred twenty-one".