21211370 has 16 divisors (see below), whose sum is σ = 38611080. Its totient is φ = 8388864.

The previous prime is 21211369. The next prime is 21211373. The reversal of 21211370 is 7311212.

It can be written as a sum of positive squares in 4 ways, for example, as 17799961 + 3411409 = 4219^2 + 1847^2 .

It is not an unprimeable number, because it can be changed into a prime (21211373) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11027 + ... + 12806.

Almost surely, 2^21211370 is an apocalyptic number.

21211370 is a deficient number, since it is larger than the sum of its proper divisors (17399710).

21211370 is a wasteful number, since it uses less digits than its factorization.

21211370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23929.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21211370 is about 4605.5803108837. The cubic root of 21211370 is about 276.8149702468.

Adding to 21211370 its reverse (7311212), we get a palindrome (28522582).

The spelling of 21211370 in words is "twenty-one million, two hundred eleven thousand, three hundred seventy".