19664390 has 16 divisors (see below), whose sum is σ = 36353232. Its totient is φ = 7653024.

The previous prime is 19664357. The next prime is 19664399. The reversal of 19664390 is 9346691.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19664399) 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, 26204 + ... + 26943.

It is an arithmetic number, because the mean of its divisors is an integer number (2272077).

Almost surely, 2^19664390 is an apocalyptic number.

19664390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19664390 is a deficient number, since it is larger than the sum of its proper divisors (16688842).

19664390 is a wasteful number, since it uses less digits than its factorization.

19664390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53191.

The product of its (nonzero) digits is 34992, while the sum is 38.

The square root of 19664390 is about 4434.4548706690. The cubic root of 19664390 is about 269.9148794319.

The spelling of 19664390 in words is "nineteen million, six hundred sixty-four thousand, three hundred ninety".