19731940 has 12 divisors (see below), whose sum is σ = 41437116. Its totient is φ = 7892768.

The previous prime is 19731911. The next prime is 19731941. The reversal of 19731940 is 4913791.

It can be written as a sum of positive squares in 2 ways, for example, as 7001316 + 12730624 = 2646^2 + 3568^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19731896 and 19731905.

It is not an unprimeable number, because it can be changed into a prime (19731941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 493279 + ... + 493318.

It is an arithmetic number, because the mean of its divisors is an integer number (3453093).

Almost surely, 2^19731940 is an apocalyptic number.

19731940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19731940 is an abundant number, since it is smaller than the sum of its proper divisors (21705176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19731940 is a wasteful number, since it uses less digits than its factorization.

19731940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 986606 (or 986604 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 19731940 is about 4442.0648351864. The cubic root of 19731940 is about 270.2235916521.

The spelling of 19731940 in words is "nineteen million, seven hundred thirty-one thousand, nine hundred forty".