21187699 has 6 divisors (see below), whose sum is σ = 22943076. Its totient is φ = 19557720.

The previous prime is 21187697. The next prime is 21187753. The reversal of 21187699 is 99678112.

It is not a de Polignac number, because 21187699 - 2¹ = 21187697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21187697) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62517 + ... + 62854.

It is an arithmetic number, because the mean of its divisors is an integer number (3823846).

Almost surely, 2^21187699 is an apocalyptic number.

21187699 is a deficient number, since it is larger than the sum of its proper divisors (1755377).

21187699 is a wasteful number, since it uses less digits than its factorization.

21187699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125397 (or 125384 counting only the distinct ones).

The product of its digits is 54432, while the sum is 43.

The square root of 21187699 is about 4603.0097762225. The cubic root of 21187699 is about 276.7119606172.

The spelling of 21187699 in words is "twenty-one million, one hundred eighty-seven thousand, six hundred ninety-nine".