21305378 has 8 divisors (see below), whose sum is σ = 32003868. Its totient is φ = 10637424.

The previous prime is 21305357. The next prime is 21305399. The reversal of 21305378 is 87350312.

It is an interprime number because it is at equal distance from previous prime (21305357) and next prime (21305399).

It can be written as a sum of positive squares in 2 ways, for example, as 18722929 + 2582449 = 4327^2 + 1607^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21305378.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5801 + ... + 8732.

Almost surely, 2^21305378 is an apocalyptic number.

21305378 is a deficient number, since it is larger than the sum of its proper divisors (10698490).

21305378 is a wasteful number, since it uses less digits than its factorization.

21305378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15268.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21305378 is about 4615.7749078568. The cubic root of 21305378 is about 277.2233121258.

The spelling of 21305378 in words is "twenty-one million, three hundred five thousand, three hundred seventy-eight".