21000286 has 4 divisors (see below), whose sum is σ = 31500432. Its totient is φ = 10500142.

The previous prime is 21000277. The next prime is 21000293. The reversal of 21000286 is 68200012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250070 + ... + 5250073.

It is an arithmetic number, because the mean of its divisors is an integer number (7875108).

Almost surely, 2^21000286 is an apocalyptic number.

21000286 is a deficient number, since it is larger than the sum of its proper divisors (10500146).

21000286 is a wasteful number, since it uses less digits than its factorization.

21000286 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500145.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21000286 is about 4582.6069000079. The cubic root of 21000286 is about 275.8936700964.

Adding to 21000286 its reverse (68200012), we get a palindrome (89200298).

The spelling of 21000286 in words is "twenty-one million, two hundred eighty-six", and thus it is an aban number.