21021111240 has 64 divisors (see below), whose sum is σ = 63217670400. Its totient is φ = 5591910912.

The previous prime is 21021111227. The next prime is 21021111311. The reversal of 21021111240 is 4211112012.

It is a Harshad number since it is a multiple of its sum of digits (15).

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, 165072 + ... + 263231.

It is an arithmetic number, because the mean of its divisors is an integer number (987776100).

Almost surely, 2^21021111240 is an apocalyptic number.

21021111240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021111240 is an abundant number, since it is smaller than the sum of its proper divisors (42196559160).

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

21021111240 is a wasteful number, since it uses less digits than its factorization.

21021111240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428726 (or 428722 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21021111240 its reverse (4211112012), we get a palindrome (25232223252).

The spelling of 21021111240 in words is "twenty-one billion, twenty-one million, one hundred eleven thousand, two hundred forty".