21020513149973 has 4 divisors (see below), whose sum is σ = 22126855947360. Its totient is φ = 19914170352588.

The previous prime is 21020513149949. The next prime is 21020513150059. The reversal of 21020513149973 is 37994131502012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21020513149973 - 2²⁰ = 21020512101397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020513149073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 553171398665 + ... + 553171398702.

It is an arithmetic number, because the mean of its divisors is an integer number (5531713986840).

Almost surely, 2^{21020513149973} is an apocalyptic number.

It is an amenable number.

21020513149973 is a deficient number, since it is larger than the sum of its proper divisors (1106342797387).

21020513149973 is a wasteful number, since it uses less digits than its factorization.

21020513149973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1106342797386.

The product of its (nonzero) digits is 408240, while the sum is 47.

The spelling of 21020513149973 in words is "twenty-one trillion, twenty billion, five hundred thirteen million, one hundred forty-nine thousand, nine hundred seventy-three".