21371386 has 4 divisors (see below), whose sum is σ = 32057082. Its totient is φ = 10685692.

The previous prime is 21371377. The next prime is 21371401. The reversal of 21371386 is 68317312.

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., 12780625 + 8590761 = 3575^2 + 2931^2 .

It is a super-2 number, since 2×21371386² = 913472279121992, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5342845 + ... + 5342848.

Almost surely, 2^21371386 is an apocalyptic number.

21371386 is a deficient number, since it is larger than the sum of its proper divisors (10685696).

21371386 is a wasteful number, since it uses less digits than its factorization.

21371386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10685695.

The product of its digits is 6048, while the sum is 31.

The square root of 21371386 is about 4622.9196402274. The cubic root of 21371386 is about 277.5093133254.

Adding to 21371386 its reverse (68317312), we get a palindrome (89688698).

The spelling of 21371386 in words is "twenty-one million, three hundred seventy-one thousand, three hundred eighty-six".