63871921 has 2 divisors, whose sum is σ = 63871922. Its totient is φ = 63871920.

The previous prime is 63871909. The next prime is 63871933. The reversal of 63871921 is 12917836.

It is a balanced prime because it is at equal distance from previous prime (63871909) and next prime (63871933).

It can be written as a sum of positive squares in only one way, i.e., 49914225 + 13957696 = 7065^2 + 3736^2 .

It is a cyclic number.

It is not a de Polignac number, because 63871921 - 2⁷ = 63871793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (63871991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31935960 + 31935961.

It is an arithmetic number, because the mean of its divisors is an integer number (31935961).

Almost surely, 2^63871921 is an apocalyptic number.

It is an amenable number.

63871921 is a deficient number, since it is larger than the sum of its proper divisors (1).

63871921 is an equidigital number, since it uses as much as digits as its factorization.

63871921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 37.

The square root of 63871921 is about 7991.9910535485. The cubic root of 63871921 is about 399.7329905545.

The spelling of 63871921 in words is "sixty-three million, eight hundred seventy-one thousand, nine hundred twenty-one".