21899679 has 8 divisors (see below), whose sum is σ = 29694720. Its totient is φ = 14352216.

The previous prime is 21899677. The next prime is 21899707. The reversal of 21899679 is 97699812.

It is a happy number.

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

It is not a de Polignac number, because 21899679 - 2¹ = 21899677 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21899677) 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, 61687 + ... + 62040.

It is an arithmetic number, because the mean of its divisors is an integer number (3711840).

Almost surely, 2^21899679 is an apocalyptic number.

21899679 is a deficient number, since it is larger than the sum of its proper divisors (7795041).

21899679 is a wasteful number, since it uses less digits than its factorization.

21899679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123789.

The product of its digits is 489888, while the sum is 51.

The square root of 21899679 is about 4679.7092858424. The cubic root of 21899679 is about 279.7773698006. Note that the first 3 decimals are identical.

It can be divided in two parts, 21899 and 679, that added together give a triangular number (22578 = T₂₁₂).

The spelling of 21899679 in words is "twenty-one million, eight hundred ninety-nine thousand, six hundred seventy-nine".