21309781158 has 40 divisors (see below), whose sum is σ = 48860168808. Its totient is φ = 6938066016.

The previous prime is 21309781121. The next prime is 21309781159. The reversal of 21309781158 is 85118790312.

21309781158 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21309781159) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1522591 + ... + 1536522.

Almost surely, 2^21309781158 is an apocalyptic number.

21309781158 is an abundant number, since it is smaller than the sum of its proper divisors (27550387650).

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

21309781158 is a wasteful number, since it uses less digits than its factorization.

21309781158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3059170 (or 3059161 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 45.

The spelling of 21309781158 in words is "twenty-one billion, three hundred nine million, seven hundred eighty-one thousand, one hundred fifty-eight".