21199659 has 16 divisors (see below), whose sum is σ = 30549792. Its totient is φ = 12999168.

The previous prime is 21199643. The next prime is 21199681. The reversal of 21199659 is 95699112.

21199659 = 1271² + 1272² + ... + 1283².

It is a happy number.

It is not a de Polignac number, because 21199659 - 2⁴ = 21199643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21199659.

It is not an unprimeable number, because it can be changed into a prime (21199639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12337 + ... + 13949.

It is an arithmetic number, because the mean of its divisors is an integer number (1909362).

Almost surely, 2^21199659 is an apocalyptic number.

21199659 is a deficient number, since it is larger than the sum of its proper divisors (9350133).

21199659 is a wasteful number, since it uses less digits than its factorization.

21199659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966.

The product of its digits is 43740, while the sum is 42.

The square root of 21199659 is about 4604.3087429059. The cubic root of 21199659 is about 276.7640168053.

The spelling of 21199659 in words is "twenty-one million, one hundred ninety-nine thousand, six hundred fifty-nine".