21899643571 has 4 divisors (see below), whose sum is σ = 23584231552. Its totient is φ = 20215055592.

The previous prime is 21899643569. The next prime is 21899643589. The reversal of 21899643571 is 17534699812.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21899643571 - 2¹ = 21899643569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21899683571) 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, 842293971 + ... + 842293996.

It is an arithmetic number, because the mean of its divisors is an integer number (5896057888).

Almost surely, 2^21899643571 is an apocalyptic number.

21899643571 is a deficient number, since it is larger than the sum of its proper divisors (1684587981).

21899643571 is a wasteful number, since it uses less digits than its factorization.

21899643571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1684587980.

The product of its digits is 3265920, while the sum is 55.

The spelling of 21899643571 in words is "twenty-one billion, eight hundred ninety-nine million, six hundred forty-three thousand, five hundred seventy-one".