21431304240 has 40 divisors (see below), whose sum is σ = 66437043888. Its totient is φ = 5715014400.

The previous prime is 21431304227. The next prime is 21431304247. The reversal of 21431304240 is 4240313412.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21431304240.

It is not an unprimeable number, because it can be changed into a prime (21431304247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44648311 + ... + 44648790.

Almost surely, 2^21431304240 is an apocalyptic number.

21431304240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21431304240 is an abundant number, since it is smaller than the sum of its proper divisors (45005739648).

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

21431304240 is a wasteful number, since it uses less digits than its factorization.

21431304240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89297117 (or 89297111 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21431304240 its reverse (4240313412), we get a palindrome (25671617652).

The spelling of 21431304240 in words is "twenty-one billion, four hundred thirty-one million, three hundred four thousand, two hundred forty".