21018670 has 8 divisors (see below), whose sum is σ = 37833624. Its totient is φ = 8407464.

The previous prime is 21018667. The next prime is 21018719. The reversal of 21018670 is 7681012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050924 + ... + 1050943.

It is an arithmetic number, because the mean of its divisors is an integer number (4729203).

Almost surely, 2^21018670 is an apocalyptic number.

21018670 is a deficient number, since it is larger than the sum of its proper divisors (16814954).

21018670 is a wasteful number, since it uses less digits than its factorization.

21018670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2101874.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21018670 is about 4584.6123064006. The cubic root of 21018670 is about 275.9741539194.

Adding to 21018670 its reverse (7681012), we get a palindrome (28699682).

The spelling of 21018670 in words is "twenty-one million, eighteen thousand, six hundred seventy".