21780757318 has 16 divisors (see below), whose sum is σ = 32839732800. Its totient is φ = 10834223400.

The previous prime is 21780757309. The next prime is 21780757321. The reversal of 21780757318 is 81375708712.

It is a super-2 number, since 2×21780757318² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1143033 + ... + 1161931.

It is an arithmetic number, because the mean of its divisors is an integer number (2052483300).

Almost surely, 2^21780757318 is an apocalyptic number.

21780757318 is a deficient number, since it is larger than the sum of its proper divisors (11058975482).

21780757318 is a wasteful number, since it uses less digits than its factorization.

21780757318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21843.

The product of its (nonzero) digits is 658560, while the sum is 49.

The spelling of 21780757318 in words is "twenty-one billion, seven hundred eighty million, seven hundred fifty-seven thousand, three hundred eighteen".