21877889 has 12 divisors (see below), whose sum is σ = 24565632. Its totient is φ = 19460760.

The previous prime is 21877883. The next prime is 21877897. The reversal of 21877889 is 98877812.

It is a happy number.

It is not a de Polignac number, because 21877889 - 2⁸ = 21877633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21877883) 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 11 ways as a sum of consecutive naturals, for example, 3764 + ... + 7610.

It is an arithmetic number, because the mean of its divisors is an integer number (2047136).

Almost surely, 2^21877889 is an apocalyptic number.

It is an amenable number.

21877889 is a deficient number, since it is larger than the sum of its proper divisors (2687743).

21877889 is a wasteful number, since it uses less digits than its factorization.

21877889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3916 (or 3905 counting only the distinct ones).

The product of its digits is 451584, while the sum is 50.

The square root of 21877889 is about 4677.3805703620. The cubic root of 21877889 is about 279.6845469493.

The spelling of 21877889 in words is "twenty-one million, eight hundred seventy-seven thousand, eight hundred eighty-nine".