21886091 has 4 divisors (see below), whose sum is σ = 22031184. Its totient is φ = 21741000.

The previous prime is 21886063. The next prime is 21886103. The reversal of 21886091 is 19068812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21886091 - 2⁶ = 21886027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21886061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72320 + ... + 72621.

It is an arithmetic number, because the mean of its divisors is an integer number (5507796).

Almost surely, 2^21886091 is an apocalyptic number.

21886091 is a deficient number, since it is larger than the sum of its proper divisors (145093).

21886091 is a wasteful number, since it uses less digits than its factorization.

21886091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145092.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 21886091 is about 4678.2572609894. The cubic root of 21886091 is about 279.7194937403.

The spelling of 21886091 in words is "twenty-one million, eight hundred eighty-six thousand, ninety-one".