20666519 has 8 divisors (see below), whose sum is σ = 21164592. Its totient is φ = 20174400.

The previous prime is 20666453. The next prime is 20666521. The reversal of 20666519 is 91566602.

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 20666519 - 2⁸ = 20666263 is a prime.

It is a super-2 number, since 2×20666519² = 854210015154722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20666539) 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, 5972 + ... + 8774.

It is an arithmetic number, because the mean of its divisors is an integer number (2645574).

Almost surely, 2^20666519 is an apocalyptic number.

20666519 is a deficient number, since it is larger than the sum of its proper divisors (498073).

20666519 is a wasteful number, since it uses less digits than its factorization.

20666519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2977.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 20666519 is about 4546.0443244650. The cubic root of 20666519 is about 274.4242234181.

The spelling of 20666519 in words is "twenty million, six hundred sixty-six thousand, five hundred nineteen".