21678652 has 6 divisors (see below), whose sum is σ = 37937648. Its totient is φ = 10839324.

The previous prime is 21678623. The next prime is 21678659. The reversal of 21678652 is 25687612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21678659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2709828 + ... + 2709835.

Almost surely, 2^21678652 is an apocalyptic number.

It is an amenable number.

21678652 is a deficient number, since it is larger than the sum of its proper divisors (16258996).

21678652 is a wasteful number, since it uses less digits than its factorization.

21678652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5419667 (or 5419665 counting only the distinct ones).

The product of its digits is 40320, while the sum is 37.

The square root of 21678652 is about 4656.0339345842. The cubic root of 21678652 is about 278.8329485626.

The spelling of 21678652 in words is "twenty-one million, six hundred seventy-eight thousand, six hundred fifty-two".