211220018 has 4 divisors (see below), whose sum is σ = 316830030. Its totient is φ = 105610008.

The previous prime is 211220011. The next prime is 211220027. The reversal of 211220018 is 810022112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 131171209 + 80048809 = 11453^2 + 8947^2 .

It is a super-2 number, since 2×211220018² = 89227792007840648, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211219978 and 211220005.

It is not an unprimeable number, because it can be changed into a prime (211220011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52805003 + ... + 52805006.

Almost surely, 2^211220018 is an apocalyptic number.

211220018 is a deficient number, since it is larger than the sum of its proper divisors (105610012).

211220018 is a wasteful number, since it uses less digits than its factorization.

211220018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105610011.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 211220018 is about 14533.4104049944. The cubic root of 211220018 is about 595.5410355553.

The spelling of 211220018 in words is "two hundred eleven million, two hundred twenty thousand, eighteen".