21018700 has 18 divisors (see below), whose sum is σ = 45610796. Its totient is φ = 8407440.

The previous prime is 21018667. The next prime is 21018719. The reversal of 21018700 is 781012.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 104994 + ... + 105193.

Almost surely, 2^21018700 is an apocalyptic number.

21018700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21018700 is an abundant number, since it is smaller than the sum of its proper divisors (24592096).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21018700 is a wasteful number, since it uses less digits than its factorization.

21018700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210201 (or 210194 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 21018700 is about 4584.6155782137. The cubic root of 21018700 is about 275.9742852189.

Adding to 21018700 its reverse (781012), we get a palindrome (21799712).

It can be divided in two parts, 21018 and 700, that multiplied together give a triangular number (14712600 = T₅₄₂₄).

The spelling of 21018700 in words is "twenty-one million, eighteen thousand, seven hundred".