21012221047 has 2 divisors, whose sum is σ = 21012221048. Its totient is φ = 21012221046.

The previous prime is 21012220969. The next prime is 21012221057. The reversal of 21012221047 is 74012221012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21012221047 - 2¹⁵ = 21012188279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012221057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506110523 + 10506110524.

It is an arithmetic number, because the mean of its divisors is an integer number (10506110524).

Almost surely, 2^21012221047 is an apocalyptic number.

21012221047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012221047 is an equidigital number, since it uses as much as digits as its factorization.

21012221047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 22.

Adding to 21012221047 its reverse (74012221012), we get a palindrome (95024442059).

The spelling of 21012221047 in words is "twenty-one billion, twelve million, two hundred twenty-one thousand, forty-seven".