21388345 has 8 divisors (see below), whose sum is σ = 27999360. Its totient is φ = 15555120.

The previous prime is 21388333. The next prime is 21388373. The reversal of 21388345 is 54388312.

It is a happy number.

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

It is not a de Polignac number, because 21388345 - 2⁵ = 21388313 is a prime.

It is a super-2 number, since 2×21388345² = 914922603678050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21388345.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194385 + ... + 194494.

It is an arithmetic number, because the mean of its divisors is an integer number (3499920).

Almost surely, 2^21388345 is an apocalyptic number.

It is an amenable number.

21388345 is a deficient number, since it is larger than the sum of its proper divisors (6611015).

21388345 is a wasteful number, since it uses less digits than its factorization.

21388345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388895.

The product of its digits is 23040, while the sum is 34.

The square root of 21388345 is about 4624.7535069450. The cubic root of 21388345 is about 277.5826986161.

The spelling of 21388345 in words is "twenty-one million, three hundred eighty-eight thousand, three hundred forty-five".