3971821861079 has 2 divisors, whose sum is σ = 3971821861080. Its totient is φ = 3971821861078.

The previous prime is 3971821861057. The next prime is 3971821861081. The reversal of 3971821861079 is 9701681281793.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3971821861079 is a prime.

It is a super-2 number, since 2×3971821861079² (a number of 26 digits) contains 22 as substring.

Together with 3971821861081, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3971821861099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1985910930539 + 1985910930540.

It is an arithmetic number, because the mean of its divisors is an integer number (1985910930540).

Almost surely, 2^{3971821861079} is an apocalyptic number.

3971821861079 is a deficient number, since it is larger than the sum of its proper divisors (1).

3971821861079 is an equidigital number, since it uses as much as digits as its factorization.

3971821861079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9144576, while the sum is 62.

The spelling of 3971821861079 in words is "three trillion, nine hundred seventy-one billion, eight hundred twenty-one million, eight hundred sixty-one thousand, seventy-nine".