21718851870 has 32 divisors (see below), whose sum is σ = 52445043072. Its totient is φ = 5756160672.

The previous prime is 21718851851. The next prime is 21718851871. The reversal of 21718851870 is 7815881712.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21718851871) 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, 2215852 + ... + 2225631.

It is an arithmetic number, because the mean of its divisors is an integer number (1638907596).

Almost surely, 2^21718851870 is an apocalyptic number.

21718851870 is an abundant number, since it is smaller than the sum of its proper divisors (30726191202).

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

21718851870 is a wasteful number, since it uses less digits than its factorization.

21718851870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4441656.

The product of its (nonzero) digits is 250880, while the sum is 48.

The spelling of 21718851870 in words is "twenty-one billion, seven hundred eighteen million, eight hundred fifty-one thousand, eight hundred seventy".