20615868 has 216 divisors, whose sum is σ = 69713280. Its totient is φ = 5080320.

The previous prime is 20615867. The next prime is 20615873. The reversal of 20615868 is 86851602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20615867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 665013 + ... + 665043.

Almost surely, 2^20615868 is an apocalyptic number.

20615868 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20615868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34856640).

20615868 is an abundant number, since it is smaller than the sum of its proper divisors (49097412).

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

20615868 is a wasteful number, since it uses less digits than its factorization.

20615868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 85 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20615868 is about 4540.4700197226. The cubic root of 20615868 is about 274.1998470984.

The spelling of 20615868 in words is "twenty million, six hundred fifteen thousand, eight hundred sixty-eight".