21879691 has 8 divisors (see below), whose sum is σ = 23020704. Its totient is φ = 20767680.

The previous prime is 21879661. The next prime is 21879701. The reversal of 21879691 is 19697812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21879691 - 2⁷ = 21879563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21879631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5695 + ... + 8728.

It is an arithmetic number, because the mean of its divisors is an integer number (2877588).

Almost surely, 2^21879691 is an apocalyptic number.

21879691 is a deficient number, since it is larger than the sum of its proper divisors (1141013).

21879691 is a wasteful number, since it uses less digits than its factorization.

21879691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14501.

The product of its digits is 54432, while the sum is 43.

The square root of 21879691 is about 4677.5731955791. The cubic root of 21879691 is about 279.6922255956.

The spelling of 21879691 in words is "twenty-one million, eight hundred seventy-nine thousand, six hundred ninety-one".