21898901 has 2 divisors, whose sum is σ = 21898902. Its totient is φ = 21898900.

The previous prime is 21898889. The next prime is 21898909. The reversal of 21898901 is 10989812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12602500 + 9296401 = 3550^2 + 3049^2 .

It is a cyclic number.

It is not a de Polignac number, because 21898901 - 2⁶ = 21898837 is a prime.

It is a Chen prime.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21898909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10949450 + 10949451.

It is an arithmetic number, because the mean of its divisors is an integer number (10949451).

Almost surely, 2^21898901 is an apocalyptic number.

It is an amenable number.

21898901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21898901 is an equidigital number, since it uses as much as digits as its factorization.

21898901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 21898901 is about 4679.6261602825. The cubic root of 21898901 is about 279.7740566718.

The spelling of 21898901 in words is "twenty-one million, eight hundred ninety-eight thousand, nine hundred one".