21345417 has 16 divisors (see below), whose sum is σ = 33288000. Its totient is φ = 13480992.

The previous prime is 21345413. The next prime is 21345427. The reversal of 21345417 is 71454312.

It is not a de Polignac number, because 21345417 - 2² = 21345413 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (21345413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20292 + ... + 21317.

It is an arithmetic number, because the mean of its divisors is an integer number (2080500).

Almost surely, 2^21345417 is an apocalyptic number.

21345417 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21345417 is a deficient number, since it is larger than the sum of its proper divisors (11942583).

21345417 is a wasteful number, since it uses less digits than its factorization.

21345417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41637 (or 41631 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21345417 is about 4620.1100636240. The cubic root of 21345417 is about 277.3968645223.

Adding to 21345417 its reverse (71454312), we get a palindrome (92799729).

The spelling of 21345417 in words is "twenty-one million, three hundred forty-five thousand, four hundred seventeen".