21190086 has 48 divisors (see below), whose sum is σ = 48484800. Its totient is φ = 6934248.

The previous prime is 21190079. The next prime is 21190093. The reversal of 21190086 is 68009112.

It is an interprime number because it is at equal distance from previous prime (21190079) and next prime (21190093).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28305 + ... + 29043.

It is an arithmetic number, because the mean of its divisors is an integer number (1010100).

Almost surely, 2^21190086 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21190086, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24242400).

21190086 is an abundant number, since it is smaller than the sum of its proper divisors (27294714).

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

21190086 is an equidigital number, since it uses as much as digits as its factorization.

21190086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815 (or 803 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 21190086 is about 4603.2690557907. The cubic root of 21190086 is about 276.7223516566.

Adding to 21190086 its reverse (68009112), we get a palindrome (89199198).

The spelling of 21190086 in words is "twenty-one million, one hundred ninety thousand, eighty-six".