21004353899 has 4 divisors (see below), whose sum is σ = 21004804464. Its totient is φ = 21003903336.

The previous prime is 21004353889. The next prime is 21004353901. The reversal of 21004353899 is 99835340012.

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 21004353899 - 2²⁴ = 20987576683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004353829) 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, 146072 + ... + 251685.

It is an arithmetic number, because the mean of its divisors is an integer number (5251201116).

Almost surely, 2^21004353899 is an apocalyptic number.

21004353899 is a deficient number, since it is larger than the sum of its proper divisors (450565).

21004353899 is an equidigital number, since it uses as much as digits as its factorization.

21004353899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450564.

The product of its (nonzero) digits is 233280, while the sum is 44.

The spelling of 21004353899 in words is "twenty-one billion, four million, three hundred fifty-three thousand, eight hundred ninety-nine".