21398205 has 16 divisors (see below), whose sum is σ = 34295040. Its totient is φ = 11393088.

The previous prime is 21398191. The next prime is 21398227. The reversal of 21398205 is 50289312.

It is a happy number.

It is not a de Polignac number, because 21398205 - 2⁶ = 21398141 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14899 + ... + 16271.

It is an arithmetic number, because the mean of its divisors is an integer number (2143440).

Almost surely, 2^21398205 is an apocalyptic number.

It is an amenable number.

21398205 is a deficient number, since it is larger than the sum of its proper divisors (12896835).

21398205 is a wasteful number, since it uses less digits than its factorization.

21398205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 21398205 is about 4625.8193868762. The cubic root of 21398205 is about 277.6253471541.

The spelling of 21398205 in words is "twenty-one million, three hundred ninety-eight thousand, two hundred five".