21608078 has 4 divisors (see below), whose sum is σ = 32412120. Its totient is φ = 10804038.

The previous prime is 21608077. The next prime is 21608089. The reversal of 21608078 is 87080612.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21608077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5402018 + ... + 5402021.

It is an arithmetic number, because the mean of its divisors is an integer number (8103030).

Almost surely, 2^21608078 is an apocalyptic number.

21608078 is a deficient number, since it is larger than the sum of its proper divisors (10804042).

21608078 is a wasteful number, since it uses less digits than its factorization.

21608078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10804041.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 21608078 is about 4648.4489886413. The cubic root of 21608078 is about 278.5300430552.

The spelling of 21608078 in words is "twenty-one million, six hundred eight thousand, seventy-eight".