21440121240 has 64 divisors (see below), whose sum is σ = 64910498400. Its totient is φ = 5664909312.

The previous prime is 21440121233. The next prime is 21440121247. The reversal of 21440121240 is 4212104412.

It is an interprime number because it is at equal distance from previous prime (21440121233) and next prime (21440121247).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440121247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 806497 + ... + 832656.

Almost surely, 2^21440121240 is an apocalyptic number.

21440121240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21440121240 is an abundant number, since it is smaller than the sum of its proper divisors (43470377160).

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

21440121240 is a wasteful number, since it uses less digits than its factorization.

21440121240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1639276 (or 1639272 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21440121240 its reverse (4212104412), we get a palindrome (25652225652).

It can be divided in two parts, 214401 and 21240, that added together give a triangular number (235641 = T₆₈₆).

The spelling of 21440121240 in words is "twenty-one billion, four hundred forty million, one hundred twenty-one thousand, two hundred forty".