19706921 has 12 divisors (see below), whose sum is σ = 22080780. Its totient is φ = 17559360.

The previous prime is 19706909. The next prime is 19706941. The reversal of 19706921 is 12960791.

It can be written as a sum of positive squares in 6 ways, for example, as 7182400 + 12524521 = 2680^2 + 3539^2 .

It is a de Polignac number, because none of the positive numbers 2^k-19706921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19706941) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 2891 + ... + 6911.

It is an arithmetic number, because the mean of its divisors is an integer number (1840065).

Almost surely, 2^19706921 is an apocalyptic number.

It is an amenable number.

19706921 is a deficient number, since it is larger than the sum of its proper divisors (2373859).

19706921 is a wasteful number, since it uses less digits than its factorization.

19706921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4076 (or 4063 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 19706921 is about 4439.2477966430. The cubic root of 19706921 is about 270.1093338639.

The spelling of 19706921 in words is "nineteen million, seven hundred six thousand, nine hundred twenty-one".