21699493 has 4 divisors (see below), whose sum is σ = 21902400. Its totient is φ = 21496588.

The previous prime is 21699481. The next prime is 21699499. The reversal of 21699493 is 39499612.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21699493 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 (21699499) 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, 101293 + ... + 101506.

It is an arithmetic number, because the mean of its divisors is an integer number (5475600).

Almost surely, 2^21699493 is an apocalyptic number.

It is an amenable number.

21699493 is a deficient number, since it is larger than the sum of its proper divisors (202907).

21699493 is a wasteful number, since it uses less digits than its factorization.

21699493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202906.

The product of its digits is 104976, while the sum is 43.

The square root of 21699493 is about 4658.2714605313. The cubic root of 21699493 is about 278.9222729399.

The spelling of 21699493 in words is "twenty-one million, six hundred ninety-nine thousand, four hundred ninety-three".