21986000 has 40 divisors (see below), whose sum is σ = 53166984. Its totient is φ = 8793600.

The previous prime is 21985979. The next prime is 21986009. The reversal of 21986000 is 68912.

It can be written as a sum of positive squares in 4 ways, for example, as 3254416 + 18731584 = 1804^2 + 4328^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21986009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3497 + ... + 7496.

Almost surely, 2^21986000 is an apocalyptic number.

21986000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21986000 is an abundant number, since it is smaller than the sum of its proper divisors (31180984).

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

21986000 is a wasteful number, since it uses less digits than its factorization.

21986000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11016 (or 11000 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21986000 is about 4688.9231173053. The cubic root of 21986000 is about 280.1444832553.

The spelling of 21986000 in words is "twenty-one million, nine hundred eighty-six thousand".