21046571813 has 2 divisors, whose sum is σ = 21046571814. Its totient is φ = 21046571812.

The previous prime is 21046571809. The next prime is 21046571827. The reversal of 21046571813 is 31817564012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16821311809 + 4225260004 = 129697^2 + 65002^2 .

It is a cyclic number.

It is not a de Polignac number, because 21046571813 - 2² = 21046571809 is a prime.

It is a super-2 number, since 2×21046571813² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21046571873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523285906 + 10523285907.

It is an arithmetic number, because the mean of its divisors is an integer number (10523285907).

Almost surely, 2^21046571813 is an apocalyptic number.

It is an amenable number.

21046571813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21046571813 is an equidigital number, since it uses as much as digits as its factorization.

21046571813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 38.

The spelling of 21046571813 in words is "twenty-one billion, forty-six million, five hundred seventy-one thousand, eight hundred thirteen".