21555833047 has 4 divisors (see below), whose sum is σ = 24635237776. Its totient is φ = 18476428320.

The previous prime is 21555833041. The next prime is 21555833053. The reversal of 21555833047 is 74033855512.

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

It is an interprime number because it is at equal distance from previous prime (21555833041) and next prime (21555833053).

It is not a de Polignac number, because 21555833047 - 2²³ = 21547444439 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21555832994 and 21555833012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555833041) 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, 1539702354 + ... + 1539702367.

It is an arithmetic number, because the mean of its divisors is an integer number (6158809444).

Almost surely, 2^21555833047 is an apocalyptic number.

21555833047 is a deficient number, since it is larger than the sum of its proper divisors (3079404729).

21555833047 is an equidigital number, since it uses as much as digits as its factorization.

21555833047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3079404728.

The product of its (nonzero) digits is 504000, while the sum is 43.

The spelling of 21555833047 in words is "twenty-one billion, five hundred fifty-five million, eight hundred thirty-three thousand, forty-seven".