19931913 has 10 divisors (see below), whose sum is σ = 29774954. Its totient is φ = 13287888.

The previous prime is 19931909. The next prime is 19931921. The reversal of 19931913 is 31913991.

It can be written as a sum of positive squares in only one way, i.e., 16257024 + 3674889 = 4032^2 + 1917^2 .

It is not a de Polignac number, because 19931913 - 2² = 19931909 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19931953) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 122956 + ... + 123117.

Almost surely, 2^19931913 is an apocalyptic number.

It is an amenable number.

19931913 is a deficient number, since it is larger than the sum of its proper divisors (9843041).

19931913 is an equidigital number, since it uses as much as digits as its factorization.

19931913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246085 (or 246076 counting only the distinct ones).

The product of its digits is 6561, while the sum is 36.

The square root of 19931913 is about 4464.5171071461. The cubic root of 19931913 is about 271.1333838652.

The spelling of 19931913 in words is "nineteen million, nine hundred thirty-one thousand, nine hundred thirteen".