21106018 has 4 divisors (see below), whose sum is σ = 31659030. Its totient is φ = 10553008.

The previous prime is 21105977. The next prime is 21106037. The reversal of 21106018 is 81060112.

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., 11202409 + 9903609 = 3347^2 + 3147^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21105986 and 21106004.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5276503 + ... + 5276506.

Almost surely, 2^21106018 is an apocalyptic number.

21106018 is a deficient number, since it is larger than the sum of its proper divisors (10553012).

21106018 is a wasteful number, since it uses less digits than its factorization.

21106018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10553011.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 21106018 is about 4594.1286442589. The cubic root of 21106018 is about 276.3559172892.

It can be divided in two parts, 2110 and 6018, that added together give a triangular number (8128 = T₁₂₇).

The spelling of 21106018 in words is "twenty-one million, one hundred six thousand, eighteen".