20858838 has 128 divisors (see below), whose sum is σ = 58834944. Its totient is φ = 4752000.

The previous prime is 20858821. The next prime is 20858843. The reversal of 20858838 is 83885802.

20858838 = 482² + 483² + ... + 558².

It is a super-2 number, since 2×20858838² = 870182245420488, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 20858838.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 138063 + ... + 138213.

It is an arithmetic number, because the mean of its divisors is an integer number (459648).

Almost surely, 2^20858838 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20858838, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29417472).

20858838 is an abundant number, since it is smaller than the sum of its proper divisors (37976106).

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

20858838 is a wasteful number, since it uses less digits than its factorization.

20858838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210.

The product of its (nonzero) digits is 122880, while the sum is 42.

The square root of 20858838 is about 4567.1476875617. The cubic root of 20858838 is about 275.2728443564.

It can be divided in two parts, 20 and 858838, that added together give a palindrome (858858).

The spelling of 20858838 in words is "twenty million, eight hundred fifty-eight thousand, eight hundred thirty-eight".