21478345 has 8 divisors (see below), whose sum is σ = 29456064. Its totient is φ = 14727984.

The previous prime is 21478339. The next prime is 21478351. The reversal of 21478345 is 54387412.

It is an interprime number because it is at equal distance from previous prime (21478339) and next prime (21478351).

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

It is a cyclic number.

It is not a de Polignac number, because 21478345 - 2³ = 21478337 is a prime.

It is a super-2 number, since 2×21478345² = 922638607878050, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21478345.

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, 306799 + ... + 306868.

It is an arithmetic number, because the mean of its divisors is an integer number (3682008).

Almost surely, 2^21478345 is an apocalyptic number.

It is an amenable number.

21478345 is a deficient number, since it is larger than the sum of its proper divisors (7977719).

21478345 is an equidigital number, since it uses as much as digits as its factorization.

21478345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 613679.

The product of its digits is 26880, while the sum is 34.

The square root of 21478345 is about 4634.4735407595. The cubic root of 21478345 is about 277.9715004513.

The spelling of 21478345 in words is "twenty-one million, four hundred seventy-eight thousand, three hundred forty-five".