20661499 has 4 divisors (see below), whose sum is σ = 21165480. Its totient is φ = 20157520.

The previous prime is 20661463. The next prime is 20661523. The reversal of 20661499 is 99416602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20661499 - 2⁹ = 20660987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20661419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 251929 + ... + 252010.

It is an arithmetic number, because the mean of its divisors is an integer number (5291370).

Almost surely, 2^20661499 is an apocalyptic number.

20661499 is a deficient number, since it is larger than the sum of its proper divisors (503981).

20661499 is an equidigital number, since it uses as much as digits as its factorization.

20661499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503980.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 20661499 is about 4545.4921625716. The cubic root of 20661499 is about 274.4020019503.

The spelling of 20661499 in words is "twenty million, six hundred sixty-one thousand, four hundred ninety-nine".