21712078 has 8 divisors (see below), whose sum is σ = 32802840. Its totient is φ = 10777800.

The previous prime is 21712063. The next prime is 21712099. The reversal of 21712078 is 87021712.

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

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 38773 + ... + 39328.

It is an arithmetic number, because the mean of its divisors is an integer number (4100355).

Almost surely, 2^21712078 is an apocalyptic number.

21712078 is a deficient number, since it is larger than the sum of its proper divisors (11090762).

21712078 is a wasteful number, since it uses less digits than its factorization.

21712078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78242.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 21712078 is about 4659.6220876805. The cubic root of 21712078 is about 278.9761844670.

The spelling of 21712078 in words is "twenty-one million, seven hundred twelve thousand, seventy-eight".