21800079 has 24 divisors (see below), whose sum is σ = 36140832. Its totient is φ = 12404160.

The previous prime is 21800059. The next prime is 21800081. The reversal of 21800079 is 97000812.

It is not a de Polignac number, because 21800079 - 2⁵ = 21800047 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21800039) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17869 + ... + 19049.

It is an arithmetic number, because the mean of its divisors is an integer number (1505868).

Almost surely, 2^21800079 is an apocalyptic number.

21800079 is a deficient number, since it is larger than the sum of its proper divisors (14340753).

21800079 is a wasteful number, since it uses less digits than its factorization.

21800079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1487 (or 1484 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 21800079 is about 4669.0554719343. The cubic root of 21800079 is about 279.3525815682.

It can be divided in two parts, 2 and 1800079, that added together give a palindrome (1800081).

The spelling of 21800079 in words is "twenty-one million, eight hundred thousand, seventy-nine".