21140404240 has 40 divisors (see below), whose sum is σ = 49510235160. Its totient is φ = 8394433536.

The previous prime is 21140404223. The next prime is 21140404279. The reversal of 21140404240 is 4240404112.

It can be written as a sum of positive squares in 4 ways, for example, as 71301136 + 21069103104 = 8444^2 + 145152^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 953475 + ... + 975394.

It is an arithmetic number, because the mean of its divisors is an integer number (1237755879).

Almost surely, 2^21140404240 is an apocalyptic number.

21140404240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21140404240 is an abundant number, since it is smaller than the sum of its proper divisors (28369830920).

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

21140404240 is a wasteful number, since it uses less digits than its factorization.

21140404240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1929019 (or 1929013 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21140404240 its reverse (4240404112), we get a palindrome (25380808352).

The spelling of 21140404240 in words is "twenty-one billion, one hundred forty million, four hundred four thousand, two hundred forty".