21043311240 has 64 divisors (see below), whose sum is σ = 72148498560. Its totient is φ = 4809899520.

The previous prime is 21043311239. The next prime is 21043311299. The reversal of 21043311240 is 4211334012.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 12524941 + ... + 12526620.

It is an arithmetic number, because the mean of its divisors is an integer number (1127320290).

Almost surely, 2^21043311240 is an apocalyptic number.

21043311240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043311240 is an abundant number, since it is smaller than the sum of its proper divisors (51105187320).

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

21043311240 is a wasteful number, since it uses less digits than its factorization.

21043311240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25051582 (or 25051578 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

Adding to 21043311240 its reverse (4211334012), we get a palindrome (25254645252).

The spelling of 21043311240 in words is "twenty-one billion, forty-three million, three hundred eleven thousand, two hundred forty".