21916901 has 2 divisors, whose sum is σ = 21916902. Its totient is φ = 21916900.

The previous prime is 21916889. The next prime is 21916967. The reversal of 21916901 is 10961912.

21916901 is nontrivially palindromic in base 2.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16394401 + 5522500 = 4049^2 + 2350^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21916901 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21916981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10958450 + 10958451.

It is an arithmetic number, because the mean of its divisors is an integer number (10958451).

Almost surely, 2^21916901 is an apocalyptic number.

It is an amenable number.

21916901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21916901 is an equidigital number, since it uses as much as digits as its factorization.

21916901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 21916901 is about 4681.5489957919. The cubic root of 21916901 is about 279.8506899524.

The spelling of 21916901 in words is "twenty-one million, nine hundred sixteen thousand, nine hundred one".