21698699 has 16 divisors (see below), whose sum is σ = 24675840. Its totient is φ = 18900000.

The previous prime is 21698689. The next prime is 21698707. The reversal of 21698699 is 99689612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21698699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21698639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79934 + ... + 80204.

It is an arithmetic number, because the mean of its divisors is an integer number (1542240).

Almost surely, 2^21698699 is an apocalyptic number.

21698699 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21698699 is a deficient number, since it is larger than the sum of its proper divisors (2977141).

21698699 is a wasteful number, since it uses less digits than its factorization.

21698699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562.

The product of its digits is 419904, while the sum is 50.

The square root of 21698699 is about 4658.1862350061. The cubic root of 21698699 is about 278.9188709098.

The spelling of 21698699 in words is "twenty-one million, six hundred ninety-eight thousand, six hundred ninety-nine".