21043515040 has 48 divisors (see below), whose sum is σ = 49807404360. Its totient is φ = 8401812480.

The previous prime is 21043515011. The next prime is 21043515041. The reversal of 21043515040 is 4051534012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13006033936 + 8037481104 = 114044^2 + 89652^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21043514996 and 21043515014.

It is not an unprimeable number, because it can be changed into a prime (21043515041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34995 + ... + 208114.

Almost surely, 2^21043515040 is an apocalyptic number.

21043515040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043515040 is an abundant number, since it is smaller than the sum of its proper divisors (28763889320).

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

21043515040 is a wasteful number, since it uses less digits than its factorization.

21043515040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243665 (or 243657 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The spelling of 21043515040 in words is "twenty-one billion, forty-three million, five hundred fifteen thousand, forty".