21843690 has 64 divisors (see below), whose sum is σ = 58769280. Its totient is φ = 5149440.

The previous prime is 21843677. The next prime is 21843697. The reversal of 21843690 is 9634812.

It is a super-2 number, since 2×21843690² = 954293585632200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21843697) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11316 + ... + 13104.

It is an arithmetic number, because the mean of its divisors is an integer number (918270).

Almost surely, 2^21843690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21843690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29384640).

21843690 is an abundant number, since it is smaller than the sum of its proper divisors (36925590).

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

21843690 is a wasteful number, since it uses less digits than its factorization.

21843690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1847.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21843690 is about 4673.7233550992. The cubic root of 21843690 is about 279.5387388528.

The spelling of 21843690 in words is "twenty-one million, eight hundred forty-three thousand, six hundred ninety".