20662399 has 4 divisors (see below), whose sum is σ = 21328960. Its totient is φ = 19995840.

The previous prime is 20662393. The next prime is 20662423. The reversal of 20662399 is 99326602.

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 20662399 - 2²¹ = 18565247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20662393) 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, 333234 + ... + 333295.

It is an arithmetic number, because the mean of its divisors is an integer number (5332240).

Almost surely, 2^20662399 is an apocalyptic number.

20662399 is a deficient number, since it is larger than the sum of its proper divisors (666561).

20662399 is an equidigital number, since it uses as much as digits as its factorization.

20662399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666560.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 20662399 is about 4545.5911606743. The cubic root of 20662399 is about 274.4059861436.

It can be divided in two parts, 2066 and 2399, that added together give a triangular number (4465 = T₉₄).

The spelling of 20662399 in words is "twenty million, six hundred sixty-two thousand, three hundred ninety-nine".