21879877 has 4 divisors (see below), whose sum is σ = 22831200. Its totient is φ = 20928556.

The previous prime is 21879841. The next prime is 21879881. The reversal of 21879877 is 77897812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21879877 - 2¹¹ = 21877829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21879877.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21879817) 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 3 ways as a sum of consecutive naturals, for example, 475627 + ... + 475672.

It is an arithmetic number, because the mean of its divisors is an integer number (5707800).

Almost surely, 2^21879877 is an apocalyptic number.

It is an amenable number.

21879877 is a deficient number, since it is larger than the sum of its proper divisors (951323).

21879877 is an equidigital number, since it uses as much as digits as its factorization.

21879877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951322.

The product of its digits is 395136, while the sum is 49.

The square root of 21879877 is about 4677.5930776415. The cubic root of 21879877 is about 279.6930181511.

The spelling of 21879877 in words is "twenty-one million, eight hundred seventy-nine thousand, eight hundred seventy-seven".