21879073 has 4 divisors (see below), whose sum is σ = 21893508. Its totient is φ = 21864640.

The previous prime is 21879047. The next prime is 21879083. The reversal of 21879073 is 37097812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 18809569 + 3069504 = 4337^2 + 1752^2 .

It is a cyclic number.

It is not a de Polignac number, because 21879073 - 2⁵ = 21879041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21879043) 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, 4636 + ... + 8077.

It is an arithmetic number, because the mean of its divisors is an integer number (5473377).

Almost surely, 2^21879073 is an apocalyptic number.

It is an amenable number.

21879073 is a deficient number, since it is larger than the sum of its proper divisors (14435).

21879073 is a wasteful number, since it uses less digits than its factorization.

21879073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14434.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 21879073 is about 4677.5071352164. The cubic root of 21879073 is about 279.6895922339.

The spelling of 21879073 in words is "twenty-one million, eight hundred seventy-nine thousand, seventy-three".