21898201 has 4 divisors (see below), whose sum is σ = 23582692. Its totient is φ = 20213712.

The previous prime is 21898189. The next prime is 21898237. The reversal of 21898201 is 10289812.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7420176 + 14478025 = 2724^2 + 3805^2 .

It is a cyclic number.

It is not a de Polignac number, because 21898201 - 2²³ = 13509593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21898271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842226 + ... + 842251.

It is an arithmetic number, because the mean of its divisors is an integer number (5895673).

Almost surely, 2^21898201 is an apocalyptic number.

It is an amenable number.

21898201 is a deficient number, since it is larger than the sum of its proper divisors (1684491).

21898201 is a wasteful number, since it uses less digits than its factorization.

21898201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1684490.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 21898201 is about 4679.5513673856. The cubic root of 21898201 is about 279.7710756405.

The spelling of 21898201 in words is "twenty-one million, eight hundred ninety-eight thousand, two hundred one".