21020330455493 has 4 divisors (see below), whose sum is σ = 21020342607948. Its totient is φ = 21020318303040.

The previous prime is 21020330455483. The next prime is 21020330455529. The reversal of 21020330455493 is 39455403302012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9577650869284 + 11442679586209 = 3094778^2 + 3382703^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020330455493 - 2³⁰ = 21019256713669 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020330455493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020330455483) 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, 2943146 + ... + 7120587.

It is an arithmetic number, because the mean of its divisors is an integer number (5255085651987).

Almost surely, 2^{21020330455493} is an apocalyptic number.

It is an amenable number.

21020330455493 is a deficient number, since it is larger than the sum of its proper divisors (12152455).

21020330455493 is a wasteful number, since it uses less digits than its factorization.

21020330455493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12152454.

The product of its (nonzero) digits is 388800, while the sum is 41.

The spelling of 21020330455493 in words is "twenty-one trillion, twenty billion, three hundred thirty million, four hundred fifty-five thousand, four hundred ninety-three".