21869107851 has 4 divisors (see below), whose sum is σ = 29158810472. Its totient is φ = 14579405232.

The previous prime is 21869107847. The next prime is 21869107867. The reversal of 21869107851 is 15870196812.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21869107851 - 2² = 21869107847 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21869107851.

It is not an unprimeable number, because it can be changed into a prime (21869102851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3644851306 + ... + 3644851311.

It is an arithmetic number, because the mean of its divisors is an integer number (7289702618).

Almost surely, 2^21869107851 is an apocalyptic number.

21869107851 is a deficient number, since it is larger than the sum of its proper divisors (7289702621).

21869107851 is an equidigital number, since it uses as much as digits as its factorization.

21869107851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7289702620.

The product of its (nonzero) digits is 241920, while the sum is 48.

The spelling of 21869107851 in words is "twenty-one billion, eight hundred sixty-nine million, one hundred seven thousand, eight hundred fifty-one".