81863437 has 2 divisors, whose sum is σ = 81863438. Its totient is φ = 81863436.

The previous prime is 81863407. The next prime is 81863447. The reversal of 81863437 is 73436818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80622441 + 1240996 = 8979^2 + 1114^2 .

It is a cyclic number.

It is not a de Polignac number, because 81863437 - 2¹¹ = 81861389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81863437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81863407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40931718 + 40931719.

It is an arithmetic number, because the mean of its divisors is an integer number (40931719).

Almost surely, 2^81863437 is an apocalyptic number.

It is an amenable number.

81863437 is a deficient number, since it is larger than the sum of its proper divisors (1).

81863437 is an equidigital number, since it uses as much as digits as its factorization.

81863437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 40.

The square root of 81863437 is about 9047.8415658100. The cubic root of 81863437 is about 434.2068375652.

The spelling of 81863437 in words is "eighty-one million, eight hundred sixty-three thousand, four hundred thirty-seven".