21938136 has 64 divisors (see below), whose sum is σ = 62449920. Its totient is φ = 6357120.

The previous prime is 21938129. The next prime is 21938149. The reversal of 21938136 is 63183912.

21938136 = T₃₅₃ + T₃₅₄ + ... + T₅₅₉.

It is a super-2 number, since 2×21938136² = 962563622308992, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21938097 and 21938106.

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, 4266 + ... + 7878.

It is an arithmetic number, because the mean of its divisors is an integer number (975780).

Almost surely, 2^21938136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21938136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31224960).

21938136 is an abundant number, since it is smaller than the sum of its proper divisors (40511784).

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

21938136 is a wasteful number, since it uses less digits than its factorization.

21938136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3656 (or 3652 counting only the distinct ones).

The product of its digits is 7776, while the sum is 33.

The square root of 21938136 is about 4683.8163926439. The cubic root of 21938136 is about 279.9410420082.

The spelling of 21938136 in words is "twenty-one million, nine hundred thirty-eight thousand, one hundred thirty-six".