21651826604773 has 4 divisors (see below), whose sum is σ = 21652013359980. Its totient is φ = 21651639849568.

The previous prime is 21651826604701. The next prime is 21651826604809. The reversal of 21651826604773 is 37740662815612.

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 2259270529569 + 19392556075204 = 1503087^2 + 4403698^2 .

It is a cyclic number.

It is not a de Polignac number, because 21651826604773 - 2¹³ = 21651826596581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21651826614773) 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, 93203590 + ... + 93435607.

It is an arithmetic number, because the mean of its divisors is an integer number (5413003339995).

Almost surely, 2^{21651826604773} is an apocalyptic number.

It is an amenable number.

21651826604773 is a deficient number, since it is larger than the sum of its proper divisors (186755207).

21651826604773 is a wasteful number, since it uses less digits than its factorization.

21651826604773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186755206.

The product of its (nonzero) digits is 20321280, while the sum is 58.

The spelling of 21651826604773 in words is "twenty-one trillion, six hundred fifty-one billion, eight hundred twenty-six million, six hundred four thousand, seven hundred seventy-three".