21678068 has 6 divisors (see below), whose sum is σ = 37936626. Its totient is φ = 10839032.

The previous prime is 21678061. The next prime is 21678071. The reversal of 21678068 is 86087612.

It can be written as a sum of positive squares in only one way, i.e., 15665764 + 6012304 = 3958^2 + 2452^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21678061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2709755 + ... + 2709762.

It is an arithmetic number, because the mean of its divisors is an integer number (6322771).

Almost surely, 2^21678068 is an apocalyptic number.

It is an amenable number.

21678068 is a deficient number, since it is larger than the sum of its proper divisors (16258558).

21678068 is a wasteful number, since it uses less digits than its factorization.

21678068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5419521 (or 5419519 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 21678068 is about 4655.9712198423. The cubic root of 21678068 is about 278.8304447184.

The spelling of 21678068 in words is "twenty-one million, six hundred seventy-eight thousand, sixty-eight".