21678414 has 16 divisors (see below), whose sum is σ = 43763328. Its totient is φ = 7158392.

The previous prime is 21678401. The next prime is 21678427. The reversal of 21678414 is 41487612.

It is an interprime number because it is at equal distance from previous prime (21678401) and next prime (21678427).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16242 + ... + 17525.

It is an arithmetic number, because the mean of its divisors is an integer number (2735208).

Almost surely, 2^21678414 is an apocalyptic number.

21678414 is an abundant number, since it is smaller than the sum of its proper divisors (22084914).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21678414 is a wasteful number, since it uses less digits than its factorization.

21678414 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33879.

The product of its digits is 10752, while the sum is 33.

The square root of 21678414 is about 4656.0083762811. The cubic root of 21678414 is about 278.8319281658.

The spelling of 21678414 in words is "twenty-one million, six hundred seventy-eight thousand, four hundred fourteen".