21886291 has 12 divisors (see below), whose sum is σ = 25667328. Its totient is φ = 18606672.

The previous prime is 21886283. The next prime is 21886313. The reversal of 21886291 is 19268812.

It is not a de Polignac number, because 21886291 - 2³ = 21886283 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21886291.

It is not an unprimeable number, because it can be changed into a prime (21886391) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4465 + ... + 7981.

It is an arithmetic number, because the mean of its divisors is an integer number (2138944).

Almost surely, 2^21886291 is an apocalyptic number.

21886291 is a deficient number, since it is larger than the sum of its proper divisors (3781037).

21886291 is a wasteful number, since it uses less digits than its factorization.

21886291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3658 (or 3651 counting only the distinct ones).

The product of its digits is 13824, while the sum is 37.

The square root of 21886291 is about 4678.2786364217. The cubic root of 21886291 is about 279.7203457841.

The spelling of 21886291 in words is "twenty-one million, eight hundred eighty-six thousand, two hundred ninety-one".