21800078 has 8 divisors (see below), whose sum is σ = 32908872. Its totient is φ = 10830456.

The previous prime is 21800059. The next prime is 21800081. The reversal of 21800078 is 87000812.

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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34400 + ... + 35027.

It is an arithmetic number, because the mean of its divisors is an integer number (4113609).

Almost surely, 2^21800078 is an apocalyptic number.

21800078 is a deficient number, since it is larger than the sum of its proper divisors (11108794).

21800078 is a wasteful number, since it uses less digits than its factorization.

21800078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69586.

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 21800078 is about 4669.0553648463. The cubic root of 21800078 is about 279.3525772968.

The spelling of 21800078 in words is "twenty-one million, eight hundred thousand, seventy-eight".