21380918 has 8 divisors (see below), whose sum is σ = 34538448. Its totient is φ = 9868104.

The previous prime is 21380893. The next prime is 21380921. The reversal of 21380918 is 81908312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 411146 + ... + 411197.

It is an arithmetic number, because the mean of its divisors is an integer number (4317306).

Almost surely, 2^21380918 is an apocalyptic number.

21380918 is a deficient number, since it is larger than the sum of its proper divisors (13157530).

21380918 is a wasteful number, since it uses less digits than its factorization.

21380918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822358.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 21380918 is about 4623.9504755133. The cubic root of 21380918 is about 277.5505651438.

The spelling of 21380918 in words is "twenty-one million, three hundred eighty thousand, nine hundred eighteen".