21113040 has 160 divisors (see below), whose sum is σ = 72245376. Its totient is φ = 5068800.

The previous prime is 21113023. The next prime is 21113041. The reversal of 21113040 is 4031112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 208990 + ... + 209090.

Almost surely, 2^21113040 is an apocalyptic number.

21113040 is a gapful number since it is divisible by the number (20) 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 21113040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36122688).

21113040 is an abundant number, since it is smaller than the sum of its proper divisors (51132336).

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

21113040 is a wasteful number, since it uses less digits than its factorization.

21113040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21113040 is about 4594.8928170307. The cubic root of 21113040 is about 276.3865618835.

Adding to 21113040 its reverse (4031112), we get a palindrome (25144152).

It can be divided in two parts, 2111 and 3040, that added together give a triangular number (5151 = T₁₀₁).

The spelling of 21113040 in words is "twenty-one million, one hundred thirteen thousand, forty".