21213610641673 has 2 divisors, whose sum is σ = 21213610641674. Its totient is φ = 21213610641672.

The previous prime is 21213610641631. The next prime is 21213610641697. The reversal of 21213610641673 is 37614601631212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11335934804544 + 9877675837129 = 3366888^2 + 3142877^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213610641673 - 2²¹ = 21213608544521 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213610641473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606805320836 + 10606805320837.

It is an arithmetic number, because the mean of its divisors is an integer number (10606805320837).

Almost surely, 2^{21213610641673} is an apocalyptic number.

It is an amenable number.

21213610641673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213610641673 is an equidigital number, since it uses as much as digits as its factorization.

21213610641673 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 43.

The spelling of 21213610641673 in words is "twenty-one trillion, two hundred thirteen billion, six hundred ten million, six hundred forty-one thousand, six hundred seventy-three".