21890201 has 2 divisors, whose sum is σ = 21890202. Its totient is φ = 21890200.

The previous prime is 21890159. The next prime is 21890213. The reversal of 21890201 is 10209812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 1819801 = 4480^2 + 1349^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21890201 is a prime.

It is not a weakly prime, because it can be changed into another prime (21890221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10945100 + 10945101.

It is an arithmetic number, because the mean of its divisors is an integer number (10945101).

Almost surely, 2^21890201 is an apocalyptic number.

It is an amenable number.

21890201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21890201 is an equidigital number, since it uses as much as digits as its factorization.

21890201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 21890201 is about 4678.6965065069. The cubic root of 21890201 is about 279.7370021990.

The spelling of 21890201 in words is "twenty-one million, eight hundred ninety thousand, two hundred one".