21889691 has 8 divisors (see below), whose sum is σ = 23100480. Its totient is φ = 20684808.

The previous prime is 21889687. The next prime is 21889717. The reversal of 21889691 is 19698812.

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 21889691 - 2² = 21889687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21889601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7640 + ... + 10106.

It is an arithmetic number, because the mean of its divisors is an integer number (2887560).

Almost surely, 2^21889691 is an apocalyptic number.

21889691 is a deficient number, since it is larger than the sum of its proper divisors (1210789).

21889691 is a wasteful number, since it uses less digits than its factorization.

21889691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2953.

The product of its digits is 62208, while the sum is 44.

The square root of 21889691 is about 4678.6420038297. The cubic root of 21889691 is about 279.7348297356.

The spelling of 21889691 in words is "twenty-one million, eight hundred eighty-nine thousand, six hundred ninety-one".