21723716371757 has 2 divisors, whose sum is σ = 21723716371758. Its totient is φ = 21723716371756.

The previous prime is 21723716371723. The next prime is 21723716371813. The reversal of 21723716371757 is 75717361732712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18982873880356 + 2740842491401 = 4356934^2 + 1655549^2 .

It is a cyclic number.

It is not a de Polignac number, because 21723716371757 - 2¹⁴ = 21723716355373 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21723716371696 and 21723716371705.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21723716377757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861858185878 + 10861858185879.

It is an arithmetic number, because the mean of its divisors is an integer number (10861858185879).

Almost surely, 2^{21723716371757} is an apocalyptic number.

It is an amenable number.

21723716371757 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723716371757 is an equidigital number, since it uses as much as digits as its factorization.

21723716371757 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18151560, while the sum is 59.

The spelling of 21723716371757 in words is "twenty-one trillion, seven hundred twenty-three billion, seven hundred sixteen million, three hundred seventy-one thousand, seven hundred fifty-seven".