21851120 has 40 divisors (see below), whose sum is σ = 53795664. Its totient is φ = 8225792.

The previous prime is 21851119. The next prime is 21851153. The reversal of 21851120 is 2115812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21851092 and 21851101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6674 + ... + 9393.

Almost surely, 2^21851120 is an apocalyptic number.

21851120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21851120 is an abundant number, since it is smaller than the sum of its proper divisors (31944544).

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

21851120 is a wasteful number, since it uses less digits than its factorization.

21851120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16097 (or 16091 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 21851120 is about 4674.5181569869. The cubic root of 21851120 is about 279.5704297345.

Adding to 21851120 its reverse (2115812), we get a palindrome (23966932).

The spelling of 21851120 in words is "twenty-one million, eight hundred fifty-one thousand, one hundred twenty".