21989869 has 8 divisors (see below), whose sum is σ = 24347808. Its totient is φ = 19691760.

The previous prime is 21989861. The next prime is 21989873. The reversal of 21989869 is 96898912.

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

It is not a de Polignac number, because 21989869 - 2³ = 21989861 is a prime.

It is a super-2 number, since 2×21989869² = 967108677274322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21989861) 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, 14182 + ... + 15655.

It is an arithmetic number, because the mean of its divisors is an integer number (3043476).

Almost surely, 2^21989869 is an apocalyptic number.

It is an amenable number.

21989869 is a deficient number, since it is larger than the sum of its proper divisors (2357939).

21989869 is a wasteful number, since it uses less digits than its factorization.

21989869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29915.

The product of its digits is 559872, while the sum is 52.

The square root of 21989869 is about 4689.3356672348. The cubic root of 21989869 is about 280.1609151579.

The spelling of 21989869 in words is "twenty-one million, nine hundred eighty-nine thousand, eight hundred sixty-nine".