21012001573 has 2 divisors, whose sum is σ = 21012001574. Its totient is φ = 21012001572.

The previous prime is 21012001559. The next prime is 21012001579. The reversal of 21012001573 is 37510021012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20515692289 + 496309284 = 143233^2 + 22278^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012001573 - 2⁵ = 21012001541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012001579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506000786 + 10506000787.

It is an arithmetic number, because the mean of its divisors is an integer number (10506000787).

Almost surely, 2^21012001573 is an apocalyptic number.

It is an amenable number.

21012001573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012001573 is an equidigital number, since it uses as much as digits as its factorization.

21012001573 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 420, while the sum is 22.

Adding to 21012001573 its reverse (37510021012), we get a palindrome (58522022585).

The spelling of 21012001573 in words is "twenty-one billion, twelve million, one thousand, five hundred seventy-three".