21699413 has 4 divisors (see below), whose sum is σ = 21709248. Its totient is φ = 21689580.

The previous prime is 21699409. The next prime is 21699439. The reversal of 21699413 is 31499612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21699413 - 2² = 21699409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21699443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98 + ... + 6588.

It is an arithmetic number, because the mean of its divisors is an integer number (5427312).

Almost surely, 2^21699413 is an apocalyptic number.

It is an amenable number.

21699413 is a deficient number, since it is larger than the sum of its proper divisors (9835).

21699413 is an equidigital number, since it uses as much as digits as its factorization.

21699413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9834.

The product of its digits is 11664, while the sum is 35.

The square root of 21699413 is about 4658.2628736472. The cubic root of 21699413 is about 278.9219301698.

The spelling of 21699413 in words is "twenty-one million, six hundred ninety-nine thousand, four hundred thirteen".