1398900021 has 4 divisors (see below), whose sum is σ = 1865200032. Its totient is φ = 932600012.

The previous prime is 1398899993. The next prime is 1398900053. The reversal of 1398900021 is 1200098931.

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 not a de Polignac number, because 1398900021 - 2⁵ = 1398899989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1398900071) 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, 233150001 + ... + 233150006.

It is an arithmetic number, because the mean of its divisors is an integer number (466300008).

Almost surely, 2^1398900021 is an apocalyptic number.

It is an amenable number.

1398900021 is a deficient number, since it is larger than the sum of its proper divisors (466300011).

1398900021 is an equidigital number, since it uses as much as digits as its factorization.

1398900021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 466300010.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 1398900021 is about 37401.8718916580. The cubic root of 1398900021 is about 1118.3958809478.

Adding to 1398900021 its reverse (1200098931), we get a palindrome (2598998952).

The spelling of 1398900021 in words is "one billion, three hundred ninety-eight million, nine hundred thousand, twenty-one".