19911964 has 24 divisors (see below), whose sum is σ = 37034928. Its totient is φ = 9335040.

The previous prime is 19911961. The next prime is 19911971. The reversal of 19911964 is 46911991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19911961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29794 + ... + 30454.

It is an arithmetic number, because the mean of its divisors is an integer number (1543122).

Almost surely, 2^19911964 is an apocalyptic number.

It is an amenable number.

19911964 is a deficient number, since it is larger than the sum of its proper divisors (17122964).

19911964 is a wasteful number, since it uses less digits than its factorization.

19911964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1125 (or 1123 counting only the distinct ones).

The product of its digits is 17496, while the sum is 40.

The square root of 19911964 is about 4462.2823756459. The cubic root of 19911964 is about 271.0428983982.

The spelling of 19911964 in words is "nineteen million, nine hundred eleven thousand, nine hundred sixty-four".