21150419921 has 2 divisors, whose sum is σ = 21150419922. Its totient is φ = 21150419920.

The previous prime is 21150419869. The next prime is 21150419929. The reversal of 21150419921 is 12991405112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21101629696 + 48790225 = 145264^2 + 6985^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21150419921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21150419929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575209960 + 10575209961.

It is an arithmetic number, because the mean of its divisors is an integer number (10575209961).

Almost surely, 2^21150419921 is an apocalyptic number.

It is an amenable number.

21150419921 is a deficient number, since it is larger than the sum of its proper divisors (1).

21150419921 is an equidigital number, since it uses as much as digits as its factorization.

21150419921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 35.

The spelling of 21150419921 in words is "twenty-one billion, one hundred fifty million, four hundred nineteen thousand, nine hundred twenty-one".