20669615 has 4 divisors (see below), whose sum is σ = 24803544. Its totient is φ = 16535688.

The previous prime is 20669611. The next prime is 20669641. The reversal of 20669615 is 51696602.

It is a happy number.

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 20669615 - 2² = 20669611 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 (20669611) 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, 2066957 + ... + 2066966.

It is an arithmetic number, because the mean of its divisors is an integer number (6200886).

Almost surely, 2^20669615 is an apocalyptic number.

20669615 is a deficient number, since it is larger than the sum of its proper divisors (4133929).

20669615 is an equidigital number, since it uses as much as digits as its factorization.

20669615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4133928.

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

The square root of 20669615 is about 4546.3848275306. The cubic root of 20669615 is about 274.4379263381.

It can be divided in two parts, 206 and 69615, that multiplied together give a triangular number (14340690 = T₅₃₅₅).

The spelling of 20669615 in words is "twenty million, six hundred sixty-nine thousand, six hundred fifteen".