21877969 has 8 divisors (see below), whose sum is σ = 22625568. Its totient is φ = 21140640.

The previous prime is 21877951. The next prime is 21878047. The reversal of 21877969 is 96977812.

It is a happy number.

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 21877969 - 2¹³ = 21869777 is a prime.

It is a super-2 number, since 2×21877969² = 957291055129922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21877939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1894 + ... + 6880.

It is an arithmetic number, because the mean of its divisors is an integer number (2828196).

Almost surely, 2^21877969 is an apocalyptic number.

It is an amenable number.

21877969 is a deficient number, since it is larger than the sum of its proper divisors (747599).

21877969 is a wasteful number, since it uses less digits than its factorization.

21877969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5135.

The product of its digits is 381024, while the sum is 49.

The square root of 21877969 is about 4677.3891221492. The cubic root of 21877969 is about 279.6848878526.

It can be divided in two parts, 218 and 77969, that added together give a palindrome (78187).

The spelling of 21877969 in words is "twenty-one million, eight hundred seventy-seven thousand, nine hundred sixty-nine".