21418036 has 6 divisors (see below), whose sum is σ = 37481570. Its totient is φ = 10709016.

The previous prime is 21418027. The next prime is 21418039. The reversal of 21418036 is 63081412.

It can be written as a sum of positive squares in only one way, i.e., 15444900 + 5973136 = 3930^2 + 2444^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21418036.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2677251 + ... + 2677258.

Almost surely, 2^21418036 is an apocalyptic number.

It is an amenable number.

21418036 is a deficient number, since it is larger than the sum of its proper divisors (16063534).

21418036 is a wasteful number, since it uses less digits than its factorization.

21418036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5354513 (or 5354511 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 21418036 is about 4627.9624026131. The cubic root of 21418036 is about 277.7110846938.

Adding to 21418036 its reverse (63081412), we get a palindrome (84499448).

The spelling of 21418036 in words is "twenty-one million, four hundred eighteen thousand, thirty-six".