21018699 has 24 divisors (see below), whose sum is σ = 32920160. Its totient is φ = 12922416.

The previous prime is 21018667. The next prime is 21018719. The reversal of 21018699 is 99681012.

It is not a de Polignac number, because 21018699 - 2⁵ = 21018667 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21018659) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19242 + ... + 20304.

Almost surely, 2^21018699 is an apocalyptic number.

21018699 is a deficient number, since it is larger than the sum of its proper divisors (11901461).

21018699 is a wasteful number, since it uses less digits than its factorization.

21018699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108 (or 1079 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 21018699 is about 4584.6154691533. The cubic root of 21018699 is about 275.9742808422.

The spelling of 21018699 in words is "twenty-one million, eighteen thousand, six hundred ninety-nine".