21517777340 has 12 divisors (see below), whose sum is σ = 45187332456. Its totient is φ = 8607110928.

The previous prime is 21517777339. The next prime is 21517777349. The reversal of 21517777340 is 4377771512.

It is a junction number, because it is equal to n+sod(n) for n = 21517777291 and 21517777300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21517777349) 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 3 ways as a sum of consecutive naturals, for example, 537944414 + ... + 537944453.

It is an arithmetic number, because the mean of its divisors is an integer number (3765611038).

Almost surely, 2^21517777340 is an apocalyptic number.

21517777340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21517777340 is an abundant number, since it is smaller than the sum of its proper divisors (23669555116).

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

21517777340 is a wasteful number, since it uses less digits than its factorization.

21517777340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075888876 (or 1075888874 counting only the distinct ones).

The product of its (nonzero) digits is 288120, while the sum is 44.

The spelling of 21517777340 in words is "twenty-one billion, five hundred seventeen million, seven hundred seventy-seven thousand, three hundred forty".