21601086 has 32 divisors (see below), whose sum is σ = 46838400. Its totient is φ = 6601824.

The previous prime is 21601061. The next prime is 21601121. The reversal of 21601086 is 68010612.

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, 11865 + ... + 13563.

It is an arithmetic number, because the mean of its divisors is an integer number (1463700).

Almost surely, 2^21601086 is an apocalyptic number.

21601086 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21601086, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23419200).

21601086 is an abundant number, since it is smaller than the sum of its proper divisors (25237314).

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

21601086 is a wasteful number, since it uses less digits than its factorization.

21601086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21601086 is about 4647.6968489780. The cubic root of 21601086 is about 278.4999973140.

Adding to 21601086 its reverse (68010612), we get a palindrome (89611698).

The spelling of 21601086 in words is "twenty-one million, six hundred one thousand, eighty-six".