21397099 has 8 divisors (see below), whose sum is σ = 22849920. Its totient is φ = 19992000.

The previous prime is 21397093. The next prime is 21397139. The reversal of 21397099 is 99079312.

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 21397099 - 2⁹ = 21396587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21397093) 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, 11002 + ... + 12799.

It is an arithmetic number, because the mean of its divisors is an integer number (2856240).

Almost surely, 2^21397099 is an apocalyptic number.

21397099 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21397099 is a deficient number, since it is larger than the sum of its proper divisors (1452821).

21397099 is a wasteful number, since it uses less digits than its factorization.

21397099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23861.

The product of its (nonzero) digits is 30618, while the sum is 40.

The square root of 21397099 is about 4625.6998389433. The cubic root of 21397099 is about 277.6205639036.

The spelling of 21397099 in words is "twenty-one million, three hundred ninety-seven thousand, ninety-nine".