21020313447 has 24 divisors (see below), whose sum is σ = 34705001760. Its totient is φ = 12009945600.

The previous prime is 21020313409. The next prime is 21020313469. The reversal of 21020313447 is 74431302012.

It is a happy number.

21020313447 is a `hidden beast` number, since 2 + 1 + 0 + 203 + 13 + 447 = 666.

It is not a de Polignac number, because 21020313447 - 2⁶ = 21020313383 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21020313447.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21028313447) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 546447 + ... + 583647.

It is an arithmetic number, because the mean of its divisors is an integer number (1446041740).

Almost surely, 2^21020313447 is an apocalyptic number.

21020313447 is a deficient number, since it is larger than the sum of its proper divisors (13684688313).

21020313447 is a wasteful number, since it uses less digits than its factorization.

21020313447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46183 (or 46180 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

Adding to 21020313447 its reverse (74431302012), we get a palindrome (95451615459).

The spelling of 21020313447 in words is "twenty-one billion, twenty million, three hundred thirteen thousand, four hundred forty-seven".