21017990047 has 2 divisors, whose sum is σ = 21017990048. Its totient is φ = 21017990046.

The previous prime is 21017990041. The next prime is 21017990083. The reversal of 21017990047 is 74009971012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21017990047 - 2³ = 21017990039 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21017989991 and 21017990009.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21017990041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508995023 + 10508995024.

It is an arithmetic number, because the mean of its divisors is an integer number (10508995024).

Almost surely, 2^21017990047 is an apocalyptic number.

21017990047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21017990047 is an equidigital number, since it uses as much as digits as its factorization.

21017990047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 40.

The spelling of 21017990047 in words is "twenty-one billion, seventeen million, nine hundred ninety thousand, forty-seven".