21299690 has 16 divisors (see below), whose sum is σ = 38693160. Its totient is φ = 8441280.

The previous prime is 21299687. The next prime is 21299701. The reversal of 21299690 is 9699212.

It can be written as a sum of positive squares in 4 ways, for example, as 16507969 + 4791721 = 4063^2 + 2189^2 .

It is a super-2 number, since 2×21299690² = 907353588192200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8681 + ... + 10860.

Almost surely, 2^21299690 is an apocalyptic number.

21299690 is a deficient number, since it is larger than the sum of its proper divisors (17393470).

21299690 is a wasteful number, since it uses less digits than its factorization.

21299690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19657.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 21299690 is about 4615.1587188308. The cubic root of 21299690 is about 277.1986393797.

The spelling of 21299690 in words is "twenty-one million, two hundred ninety-nine thousand, six hundred ninety".