21507574574566 has 4 divisors (see below), whose sum is σ = 32261361861852. Its totient is φ = 10753787287282.

The previous prime is 21507574574561. The next prime is 21507574574573. The reversal of 21507574574566 is 66547547570512.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21507574574498 and 21507574574507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21507574574561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5376893643640 + ... + 5376893643643.

It is an arithmetic number, because the mean of its divisors is an integer number (8065340465463).

Almost surely, 2^{21507574574566} is an apocalyptic number.

21507574574566 is a deficient number, since it is larger than the sum of its proper divisors (10753787287286).

21507574574566 is a wasteful number, since it uses less digits than its factorization.

21507574574566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10753787287285.

The product of its (nonzero) digits is 246960000, while the sum is 64.

The spelling of 21507574574566 in words is "twenty-one trillion, five hundred seven billion, five hundred seventy-four million, five hundred seventy-four thousand, five hundred sixty-six".