21201220049 has 2 divisors, whose sum is σ = 21201220050. Its totient is φ = 21201220048.

The previous prime is 21201220031. The next prime is 21201220123. The reversal of 21201220049 is 94002210212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19633614400 + 1567605649 = 140120^2 + 39593^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201220049 is a prime.

It is a super-3 number, since 3×21201220049³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21201220349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600610024 + 10600610025.

It is an arithmetic number, because the mean of its divisors is an integer number (10600610025).

Almost surely, 2^21201220049 is an apocalyptic number.

It is an amenable number.

21201220049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201220049 is an equidigital number, since it uses as much as digits as its factorization.

21201220049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The spelling of 21201220049 in words is "twenty-one billion, two hundred one million, two hundred twenty thousand, forty-nine".