19681905 has 32 divisors (see below), whose sum is σ = 33281280. Its totient is φ = 9912320.

The previous prime is 19681897. The next prime is 19681913. The reversal of 19681905 is 50918691.

It is an interprime number because it is at equal distance from previous prime (19681897) and next prime (19681913).

It is not a de Polignac number, because 19681905 - 2³ = 19681897 is a prime.

It is an unprimeable number.

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 in 31 ways as a sum of consecutive naturals, for example, 30385 + ... + 31025.

It is an arithmetic number, because the mean of its divisors is an integer number (1040040).

Almost surely, 2^19681905 is an apocalyptic number.

19681905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19681905 is a deficient number, since it is larger than the sum of its proper divisors (13599375).

19681905 is a wasteful number, since it uses less digits than its factorization.

19681905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 19681905 is about 4436.4293074499. The cubic root of 19681905 is about 269.9949930484.

The spelling of 19681905 in words is "nineteen million, six hundred eighty-one thousand, nine hundred five".