21152286 has 32 divisors (see below), whose sum is σ = 47473920. Its totient is φ = 6980472.

The previous prime is 21152239. The next prime is 21152291. The reversal of 21152286 is 68225112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3661 + ... + 7463.

It is an arithmetic number, because the mean of its divisors is an integer number (1483560).

Almost surely, 2^21152286 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21152286, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23736960).

21152286 is an abundant number, since it is smaller than the sum of its proper divisors (26321634).

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

21152286 is a wasteful number, since it uses less digits than its factorization.

21152286 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3917 (or 3911 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21152286 is about 4599.1614453072. The cubic root of 21152286 is about 276.5577097131.

Adding to 21152286 its reverse (68225112), we get a palindrome (89377398).

The spelling of 21152286 in words is "twenty-one million, one hundred fifty-two thousand, two hundred eighty-six".