21173733736997 has 2 divisors, whose sum is σ = 21173733736998. Its totient is φ = 21173733736996.

The previous prime is 21173733736973. The next prime is 21173733737119. The reversal of 21173733736997 is 79963733737112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19739413724836 + 1434320012161 = 4442906^2 + 1197631^2 .

It is a cyclic number.

It is not a de Polignac number, because 21173733736997 - 2⁸ = 21173733736741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21173733736907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10586866868498 + 10586866868499.

It is an arithmetic number, because the mean of its divisors is an integer number (10586866868499).

Almost surely, 2^{21173733736997} is an apocalyptic number.

It is an amenable number.

21173733736997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21173733736997 is an equidigital number, since it uses as much as digits as its factorization.

21173733736997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189035532, while the sum is 68.

The spelling of 21173733736997 in words is "twenty-one trillion, one hundred seventy-three billion, seven hundred thirty-three million, seven hundred thirty-six thousand, nine hundred ninety-seven".