21879667 has 4 divisors (see below), whose sum is σ = 21970696. Its totient is φ = 21788640.

The previous prime is 21879661. The next prime is 21879701. The reversal of 21879667 is 76697812.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21879667 - 2¹⁵ = 21846899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21879661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45153 + ... + 45634.

It is an arithmetic number, because the mean of its divisors is an integer number (5492674).

Almost surely, 2^21879667 is an apocalyptic number.

21879667 is a deficient number, since it is larger than the sum of its proper divisors (91029).

21879667 is an equidigital number, since it uses as much as digits as its factorization.

21879667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91028.

The product of its digits is 254016, while the sum is 46.

The square root of 21879667 is about 4677.5706301455. The cubic root of 21879667 is about 279.6921233300.

The spelling of 21879667 in words is "twenty-one million, eight hundred seventy-nine thousand, six hundred sixty-seven".