21053836 has 12 divisors (see below), whose sum is σ = 38032960. Its totient is φ = 10187280.

The previous prime is 21053833. The next prime is 21053839. The reversal of 21053836 is 63835012.

It is an interprime number because it is at equal distance from previous prime (21053833) and next prime (21053839).

It is a super-3 number, since 3×21053836³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21053831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84771 + ... + 85018.

Almost surely, 2^21053836 is an apocalyptic number.

It is an amenable number.

21053836 is a deficient number, since it is larger than the sum of its proper divisors (16979124).

21053836 is a wasteful number, since it uses less digits than its factorization.

21053836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169824 (or 169822 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21053836 is about 4588.4459242755. The cubic root of 21053836 is about 276.1279774764.

Adding to 21053836 its reverse (63835012), we get a palindrome (84888848).

The spelling of 21053836 in words is "twenty-one million, fifty-three thousand, eight hundred thirty-six".