19967881 has 2 divisors, whose sum is σ = 19967882. Its totient is φ = 19967880.

The previous prime is 19967839. The next prime is 19967929. The reversal of 19967881 is 18876991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18844281 + 1123600 = 4341^2 + 1060^2 .

It is a cyclic number.

It is not a de Polignac number, because 19967881 - 2¹³ = 19959689 is a prime.

It is a super-2 number, since 2×19967881² = 797432543260322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19967281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9983940 + 9983941.

It is an arithmetic number, because the mean of its divisors is an integer number (9983941).

Almost surely, 2^19967881 is an apocalyptic number.

It is an amenable number.

19967881 is a deficient number, since it is larger than the sum of its proper divisors (1).

19967881 is an equidigital number, since it uses as much as digits as its factorization.

19967881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 49.

The square root of 19967881 is about 4468.5434987253. The cubic root of 19967881 is about 271.2963765056.

The spelling of 19967881 in words is "nineteen million, nine hundred sixty-seven thousand, eight hundred eighty-one".