19639961 has 8 divisors (see below), whose sum is σ = 21498048. Its totient is φ = 17794000.

The previous prime is 19639951. The next prime is 19639967. The reversal of 19639961 is 16993691.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19639961 - 2¹⁰ = 19638937 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19639967) 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, 551 + ... + 6291.

It is an arithmetic number, because the mean of its divisors is an integer number (2687256).

Almost surely, 2^19639961 is an apocalyptic number.

19639961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19639961 is a deficient number, since it is larger than the sum of its proper divisors (1858087).

19639961 is a wasteful number, since it uses less digits than its factorization.

19639961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6063.

The product of its digits is 78732, while the sum is 44.

The square root of 19639961 is about 4431.6995611165. The cubic root of 19639961 is about 269.8030616920.

The spelling of 19639961 in words is "nineteen million, six hundred thirty-nine thousand, nine hundred sixty-one".