21950989 has 4 divisors (see below), whose sum is σ = 21962556. Its totient is φ = 21939424.

The previous prime is 21950987. The next prime is 21951043. The reversal of 21950989 is 98905912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 514089 + 21436900 = 717^2 + 4630^2 .

It is a cyclic number.

It is not a de Polignac number, because 21950989 - 2¹ = 21950987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21950983) 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, 2194 + ... + 6979.

It is an arithmetic number, because the mean of its divisors is an integer number (5490639).

Almost surely, 2^21950989 is an apocalyptic number.

It is an amenable number.

21950989 is a deficient number, since it is larger than the sum of its proper divisors (11567).

21950989 is an equidigital number, since it uses as much as digits as its factorization.

21950989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11566.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 21950989 is about 4685.1882566232. The cubic root of 21950989 is about 279.9957014646.

The spelling of 21950989 in words is "twenty-one million, nine hundred fifty thousand, nine hundred eighty-nine".