21451453673 has 4 divisors (see below), whose sum is σ = 23101565508. Its totient is φ = 19801341840.

The previous prime is 21451453669. The next prime is 21451453747. The reversal of 21451453673 is 37635415412.

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 954377449 + 20497076224 = 30893^2 + 143168^2 .

It is a cyclic number.

It is not a de Polignac number, because 21451453673 - 2² = 21451453669 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21451453673.

It is not an unprimeable number, because it can be changed into a prime (21451453273) 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, 825055898 + ... + 825055923.

It is an arithmetic number, because the mean of its divisors is an integer number (5775391377).

Almost surely, 2^21451453673 is an apocalyptic number.

It is an amenable number.

21451453673 is a deficient number, since it is larger than the sum of its proper divisors (1650111835).

21451453673 is a wasteful number, since it uses less digits than its factorization.

21451453673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650111834.

The product of its digits is 302400, while the sum is 41.

The spelling of 21451453673 in words is "twenty-one billion, four hundred fifty-one million, four hundred fifty-three thousand, six hundred seventy-three".