21378716 has 24 divisors (see below), whose sum is σ = 39360384. Its totient is φ = 10146240.

The previous prime is 21378701. The next prime is 21378733. The reversal of 21378716 is 61787312.

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, 4946 + ... + 8198.

It is an arithmetic number, because the mean of its divisors is an integer number (1640016).

Almost surely, 2^21378716 is an apocalyptic number.

It is an amenable number.

21378716 is a deficient number, since it is larger than the sum of its proper divisors (17981668).

21378716 is a wasteful number, since it uses less digits than its factorization.

21378716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3341 (or 3339 counting only the distinct ones).

The product of its digits is 14112, while the sum is 35.

The square root of 21378716 is about 4623.7123612958. The cubic root of 21378716 is about 277.5410365955.

The spelling of 21378716 in words is "twenty-one million, three hundred seventy-eight thousand, seven hundred sixteen".