21200021047 has 2 divisors, whose sum is σ = 21200021048. Its totient is φ = 21200021046.

The previous prime is 21200021027. The next prime is 21200021107. The reversal of 21200021047 is 74012000212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21200021047 - 2¹⁵ = 21199988279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21200021027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600010523 + 10600010524.

It is an arithmetic number, because the mean of its divisors is an integer number (10600010524).

Almost surely, 2^21200021047 is an apocalyptic number.

21200021047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200021047 is an equidigital number, since it uses as much as digits as its factorization.

21200021047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 19.

Adding to 21200021047 its reverse (74012000212), we get a palindrome (95212021259).

The spelling of 21200021047 in words is "twenty-one billion, two hundred million, twenty-one thousand, forty-seven".