21200421049 has 2 divisors, whose sum is σ = 21200421050. Its totient is φ = 21200421048.

The previous prime is 21200421041. The next prime is 21200421113. The reversal of 21200421049 is 94012400212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13652286649 + 7548134400 = 116843^2 + 86880^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200421049 - 2³ = 21200421041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21200421041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600210524 + 10600210525.

It is an arithmetic number, because the mean of its divisors is an integer number (10600210525).

Almost surely, 2^21200421049 is an apocalyptic number.

It is an amenable number.

21200421049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200421049 is an equidigital number, since it uses as much as digits as its factorization.

21200421049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 25.

The spelling of 21200421049 in words is "twenty-one billion, two hundred million, four hundred twenty-one thousand, forty-nine".