21999366 has 12 divisors (see below), whose sum is σ = 47665332. Its totient is φ = 7333116.

The previous prime is 21999347. The next prime is 21999379. The reversal of 21999366 is 66399912.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 611076 + ... + 611111.

It is an arithmetic number, because the mean of its divisors is an integer number (3972111).

Almost surely, 2^21999366 is an apocalyptic number.

21999366 is an abundant number, since it is smaller than the sum of its proper divisors (25665966).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21999366 is a wasteful number, since it uses less digits than its factorization.

21999366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1222195 (or 1222192 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 21999366 is about 4690.3481747094. The cubic root of 21999366 is about 280.2012413837.

The spelling of 21999366 in words is "twenty-one million, nine hundred ninety-nine thousand, three hundred sixty-six".