21011222051 has 2 divisors, whose sum is σ = 21011222052. Its totient is φ = 21011222050.

The previous prime is 21011222047. The next prime is 21011222059. The reversal of 21011222051 is 15022211012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21011222051 - 2² = 21011222047 is a prime.

It is not a weakly prime, because it can be changed into another prime (21011222059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505611025 + 10505611026.

It is an arithmetic number, because the mean of its divisors is an integer number (10505611026).

Almost surely, 2^21011222051 is an apocalyptic number.

21011222051 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011222051 is an equidigital number, since it uses as much as digits as its factorization.

21011222051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 17.

Adding to 21011222051 its reverse (15022211012), we get a palindrome (36033433063).

The spelling of 21011222051 in words is "twenty-one billion, eleven million, two hundred twenty-two thousand, fifty-one".