21620118 has 32 divisors (see below), whose sum is σ = 47216736. Its totient is φ = 6559488.

The previous prime is 21620117. The next prime is 21620129. The reversal of 21620118 is 81102612.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21620094 and 21620103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620111) 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 15 ways as a sum of consecutive naturals, for example, 3796 + ... + 7592.

It is an arithmetic number, because the mean of its divisors is an integer number (1475523).

Almost surely, 2^21620118 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21620118, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23608368).

21620118 is an abundant number, since it is smaller than the sum of its proper divisors (25596618).

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

21620118 is a wasteful number, since it uses less digits than its factorization.

21620118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3888.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21620118 is about 4649.7438639134. The cubic root of 21620118 is about 278.5817656726.

The spelling of 21620118 in words is "twenty-one million, six hundred twenty thousand, one hundred eighteen".