21366386 has 4 divisors (see below), whose sum is σ = 32049582. Its totient is φ = 10683192.

The previous prime is 21366377. The next prime is 21366391. The reversal of 21366386 is 68366312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19492225 + 1874161 = 4415^2 + 1369^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5341595 + ... + 5341598.

Almost surely, 2^21366386 is an apocalyptic number.

21366386 is a deficient number, since it is larger than the sum of its proper divisors (10683196).

21366386 is a wasteful number, since it uses less digits than its factorization.

21366386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10683195.

The product of its digits is 31104, while the sum is 35.

The square root of 21366386 is about 4622.3788248044. The cubic root of 21366386 is about 277.4876698252.

The spelling of 21366386 in words is "twenty-one million, three hundred sixty-six thousand, three hundred eighty-six".