21112380 has 48 divisors (see below), whose sum is σ = 65684640. Its totient is φ = 5629824.

The previous prime is 21112369. The next prime is 21112381. The reversal of 21112380 is 8321112.

21112380 = 470² + 471² + ... + 550².

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19009 + ... + 20088.

It is an arithmetic number, because the mean of its divisors is an integer number (1368430).

Almost surely, 2^21112380 is an apocalyptic number.

21112380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112380 is an abundant number, since it is smaller than the sum of its proper divisors (44572260).

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

21112380 is a wasteful number, since it uses less digits than its factorization.

21112380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39115 (or 39107 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 21112380 is about 4594.8209976015. The cubic root of 21112380 is about 276.3836818778.

Adding to 21112380 its reverse (8321112), we get a palindrome (29433492).

The spelling of 21112380 in words is "twenty-one million, one hundred twelve thousand, three hundred eighty".