20218907 has 4 divisors (see below), whose sum is σ = 21283080. Its totient is φ = 19154736.

The previous prime is 20218903. The next prime is 20218927. The reversal of 20218907 is 70981202.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70981202 = 2 ⋅35490601.

It is not a de Polignac number, because 20218907 - 2² = 20218903 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20218907.

It is not an unprimeable number, because it can be changed into a prime (20218903) 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, 532058 + ... + 532095.

It is an arithmetic number, because the mean of its divisors is an integer number (5320770).

Almost surely, 2^20218907 is an apocalyptic number.

20218907 is a deficient number, since it is larger than the sum of its proper divisors (1064173).

20218907 is a wasteful number, since it uses less digits than its factorization.

20218907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1064172.

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20218907 is about 4496.5438950376. The cubic root of 20218907 is about 272.4285119547.

The spelling of 20218907 in words is "twenty million, two hundred eighteen thousand, nine hundred seven".