20218961 has 8 divisors (see below), whose sum is σ = 23199360. Its totient is φ = 17261568.

The previous prime is 20218949. The next prime is 20218969. The reversal of 20218961 is 16981202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20218961 - 2⁶ = 20218897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20218969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3821 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (2899920).

Almost surely, 2^20218961 is an apocalyptic number.

It is an amenable number.

20218961 is a deficient number, since it is larger than the sum of its proper divisors (2980399).

20218961 is a wasteful number, since it uses less digits than its factorization.

20218961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11503.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 20218961 is about 4496.5498996453. The cubic root of 20218961 is about 272.4287544855.

The spelling of 20218961 in words is "twenty million, two hundred eighteen thousand, nine hundred sixty-one".