21400240312 has 16 divisors (see below), whose sum is σ = 43773219000. Its totient is φ = 9727381920.

The previous prime is 21400240297. The next prime is 21400240319. The reversal of 21400240312 is 21304200412.

It is a super-2 number, since 2×21400240312² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21400240312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400240319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121592187 + ... + 121592362.

Almost surely, 2^21400240312 is an apocalyptic number.

21400240312 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21400240312 is an abundant number, since it is smaller than the sum of its proper divisors (22372978688).

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

21400240312 is a wasteful number, since it uses less digits than its factorization.

21400240312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243184566 (or 243184562 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21400240312 its reverse (21304200412), we get a palindrome (42704440724).

The spelling of 21400240312 in words is "twenty-one billion, four hundred million, two hundred forty thousand, three hundred twelve".