21240440120 has 64 divisors (see below), whose sum is σ = 48411648000. Its totient is φ = 8386519680.

The previous prime is 21240440099. The next prime is 21240440141. The reversal of 21240440120 is 2104404212.

It is an interprime number because it is at equal distance from previous prime (21240440099) and next prime (21240440141).

It is a super-2 number, since 2×21240440120² (a number of 21 digits) contains 22 as substring.

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 = 21240440092 and 21240440101.

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, 1000415 + ... + 1021425.

It is an arithmetic number, because the mean of its divisors is an integer number (756432000).

Almost surely, 2^21240440120 is an apocalyptic number.

21240440120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21240440120 is an abundant number, since it is smaller than the sum of its proper divisors (27171207880).

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

21240440120 is a wasteful number, since it uses less digits than its factorization.

21240440120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21348 (or 21344 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21240440120 its reverse (2104404212), we get a palindrome (23344844332).

The spelling of 21240440120 in words is "twenty-one billion, two hundred forty million, four hundred forty thousand, one hundred twenty".