21018941 has 8 divisors (see below), whose sum is σ = 22014720. Its totient is φ = 20030032.

The previous prime is 21018931. The next prime is 21018947. The reversal of 21018941 is 14981012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21018941 is a prime.

It is a super-2 number, since 2×21018941² = 883591761522962, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21018941.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018947) 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, 5180 + ... + 8298.

It is an arithmetic number, because the mean of its divisors is an integer number (2751840).

Almost surely, 2^21018941 is an apocalyptic number.

It is an amenable number.

21018941 is a deficient number, since it is larger than the sum of its proper divisors (995779).

21018941 is a wasteful number, since it uses less digits than its factorization.

21018941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3435.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 21018941 is about 4584.6418616943. The cubic root of 21018941 is about 275.9753399868.

Adding to 21018941 its reverse (14981012), we get a palindrome (35999953).

It can be divided in two parts, 210 and 18941, that multiplied together give a triangular number (3977610 = T₂₈₂₀).

The spelling of 21018941 in words is "twenty-one million, eighteen thousand, nine hundred forty-one".