21078854 has 4 divisors (see below), whose sum is σ = 31618284. Its totient is φ = 10539426.

The previous prime is 21078851. The next prime is 21078857. The reversal of 21078854 is 45887012.

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

It is an interprime number because it is at equal distance from previous prime (21078851) and next prime (21078857).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21078851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5269712 + ... + 5269715.

It is an arithmetic number, because the mean of its divisors is an integer number (7904571).

Almost surely, 2^21078854 is an apocalyptic number.

21078854 is a deficient number, since it is larger than the sum of its proper divisors (10539430).

21078854 is a wasteful number, since it uses less digits than its factorization.

21078854 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10539429.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 21078854 is about 4591.1713102432. The cubic root of 21078854 is about 276.2373072798.

The spelling of 21078854 in words is "twenty-one million, seventy-eight thousand, eight hundred fifty-four".