21299861 has 8 divisors (see below), whose sum is σ = 24603264. Its totient is φ = 18224320.

The previous prime is 21299857. The next prime is 21299897. The reversal of 21299861 is 16899212.

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

It is a cyclic number.

It is not a de Polignac number, because 21299861 - 2² = 21299857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21299851) 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, 56765 + ... + 57138.

It is an arithmetic number, because the mean of its divisors is an integer number (3075408).

Almost surely, 2^21299861 is an apocalyptic number.

It is an amenable number.

21299861 is a deficient number, since it is larger than the sum of its proper divisors (3303403).

21299861 is a wasteful number, since it uses less digits than its factorization.

21299861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113931.

The product of its digits is 15552, while the sum is 38.

The square root of 21299861 is about 4615.1772447004. The cubic root of 21299861 is about 277.1993811877.

The spelling of 21299861 in words is "twenty-one million, two hundred ninety-nine thousand, eight hundred sixty-one".