21699868 has 6 divisors (see below), whose sum is σ = 37974776. Its totient is φ = 10849932.

The previous prime is 21699863. The next prime is 21699869. The reversal of 21699868 is 86899612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21699863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2712480 + ... + 2712487.

Almost surely, 2^21699868 is an apocalyptic number.

It is an amenable number.

21699868 is a deficient number, since it is larger than the sum of its proper divisors (16274908).

21699868 is a wasteful number, since it uses less digits than its factorization.

21699868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5424971 (or 5424969 counting only the distinct ones).

The product of its digits is 373248, while the sum is 49.

The square root of 21699868 is about 4658.3117113392. The cubic root of 21699868 is about 278.9238796633.

The spelling of 21699868 in words is "twenty-one million, six hundred ninety-nine thousand, eight hundred sixty-eight".