21299850 has 144 divisors (see below), whose sum is σ = 67433184. Its totient is φ = 4752000.

The previous prime is 21299843. The next prime is 21299851. The reversal of 21299850 is 5899212.

It is a super-2 number, since 2×21299850² = 907367220045000, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21299851) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 64185 + ... + 64515.

It is an arithmetic number, because the mean of its divisors is an integer number (468286).

Almost surely, 2^21299850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21299850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33716592).

21299850 is an abundant number, since it is smaller than the sum of its proper divisors (46133334).

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

21299850 is a wasteful number, since it uses less digits than its factorization.

21299850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21299850 is about 4615.1760529800. The cubic root of 21299850 is about 277.1993334692.

The spelling of 21299850 in words is "twenty-one million, two hundred ninety-nine thousand, eight hundred fifty".