20919669 has 4 divisors (see below), whose sum is σ = 27892896. Its totient is φ = 13946444.

The previous prime is 20919649. The next prime is 20919671. The reversal of 20919669 is 96691902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20919669 - 2¹³ = 20911477 is a prime.

It is a super-2 number, since 2×20919669² = 875265102139122, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20919669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20919649) 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, 3486609 + ... + 3486614.

It is an arithmetic number, because the mean of its divisors is an integer number (6973224).

Almost surely, 2^20919669 is an apocalyptic number.

It is an amenable number.

20919669 is a deficient number, since it is larger than the sum of its proper divisors (6973227).

20919669 is an equidigital number, since it uses as much as digits as its factorization.

20919669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6973226.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 20919669 is about 4573.8024662200. The cubic root of 20919669 is about 275.5401790098.

The spelling of 20919669 in words is "twenty million, nine hundred nineteen thousand, six hundred sixty-nine".