21866001671 has 2 divisors, whose sum is σ = 21866001672. Its totient is φ = 21866001670.

The previous prime is 21866001631. The next prime is 21866001701. The reversal of 21866001671 is 17610066812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21866001671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21866001631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10933000835 + 10933000836.

It is an arithmetic number, because the mean of its divisors is an integer number (10933000836).

Almost surely, 2^21866001671 is an apocalyptic number.

21866001671 is a deficient number, since it is larger than the sum of its proper divisors (1).

21866001671 is an equidigital number, since it uses as much as digits as its factorization.

21866001671 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 21866001671 in words is "twenty-one billion, eight hundred sixty-six million, one thousand, six hundred seventy-one".