21343986 has 40 divisors (see below), whose sum is σ = 48090240. Its totient is φ = 7075512.

The previous prime is 21343981. The next prime is 21343991. The reversal of 21343986 is 68934312.

21343986 is a `hidden beast` number, since 213 + 439 + 8 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21343981) and next prime (21343991).

It is a self number, because there is not a number n which added to its sum of digits gives 21343986.

It is not an unprimeable number, because it can be changed into a prime (21343981) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 57975 + ... + 58341.

It is an arithmetic number, because the mean of its divisors is an integer number (1202256).

Almost surely, 2^21343986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21343986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24045120).

21343986 is an abundant number, since it is smaller than the sum of its proper divisors (26746254).

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

21343986 is a wasteful number, since it uses less digits than its factorization.

21343986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740 (or 731 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21343986 is about 4619.9551945879. The cubic root of 21343986 is about 277.3906654744.

The spelling of 21343986 in words is "twenty-one million, three hundred forty-three thousand, nine hundred eighty-six".