21370306 has 4 divisors (see below), whose sum is σ = 32055462. Its totient is φ = 10685152.

The previous prime is 21370249. The next prime is 21370333. The reversal of 21370306 is 60307312.

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., 11162281 + 10208025 = 3341^2 + 3195^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5342575 + ... + 5342578.

Almost surely, 2^21370306 is an apocalyptic number.

21370306 is a deficient number, since it is larger than the sum of its proper divisors (10685156).

21370306 is a wasteful number, since it uses less digits than its factorization.

21370306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10685155.

The product of its (nonzero) digits is 756, while the sum is 22.

The square root of 21370306 is about 4622.8028294531. The cubic root of 21370306 is about 277.5046386152.

Adding to 21370306 its reverse (60307312), we get a palindrome (81677618).

The spelling of 21370306 in words is "twenty-one million, three hundred seventy thousand, three hundred six".