21418317 has 16 divisors (see below), whose sum is σ = 33598080. Its totient is φ = 13438656.

The previous prime is 21418261. The next prime is 21418333. The reversal of 21418317 is 71381412.

It is not a de Polignac number, because 21418317 - 2⁶ = 21418253 is a prime.

It is a super-2 number, since 2×21418317² = 917488606224978, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418337) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22873 + ... + 23790.

It is an arithmetic number, because the mean of its divisors is an integer number (2099880).

Almost surely, 2^21418317 is an apocalyptic number.

21418317 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21418317 is a deficient number, since it is larger than the sum of its proper divisors (12179763).

21418317 is a wasteful number, since it uses less digits than its factorization.

21418317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46689 (or 46683 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 21418317 is about 4627.9927614464. The cubic root of 21418317 is about 277.7122991916.

Adding to 21418317 its reverse (71381412), we get a palindrome (92799729).

The spelling of 21418317 in words is "twenty-one million, four hundred eighteen thousand, three hundred seventeen".