21850901 has 2 divisors, whose sum is σ = 21850902. Its totient is φ = 21850900.

The previous prime is 21850883. The next prime is 21850919. The reversal of 21850901 is 10905812.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21850883) and next prime (21850919).

It can be written as a sum of positive squares in only one way, i.e., 17648401 + 4202500 = 4201^2 + 2050^2 .

It is a cyclic number.

It is not a de Polignac number, because 21850901 - 2¹⁴ = 21834517 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is equal to p_1380392 and since 21850901 and 1380392 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21450901) 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 as a sum of consecutive naturals, namely, 10925450 + 10925451.

It is an arithmetic number, because the mean of its divisors is an integer number (10925451).

Almost surely, 2^21850901 is an apocalyptic number.

It is an amenable number.

21850901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21850901 is an equidigital number, since it uses as much as digits as its factorization.

21850901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 21850901 is about 4674.4947320539. The cubic root of 21850901 is about 279.5694957453.

The spelling of 21850901 in words is "twenty-one million, eight hundred fifty thousand, nine hundred one".