21636370 has 16 divisors (see below), whose sum is σ = 44509248. Its totient is φ = 7418160.

The previous prime is 21636361. The next prime is 21636371. The reversal of 21636370 is 7363612.

It is not an unprimeable number, because it can be changed into a prime (21636371) 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, 154476 + ... + 154615.

It is an arithmetic number, because the mean of its divisors is an integer number (2781828).

Almost surely, 2^21636370 is an apocalyptic number.

21636370 is an abundant number, since it is smaller than the sum of its proper divisors (22872878).

21636370 is a wasteful number, since it uses less digits than its factorization.

21636370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309105.

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 21636370 is about 4651.4911587576. The cubic root of 21636370 is about 278.6515521692.

Adding to 21636370 its reverse (7363612), we get a palindrome (28999982).

The spelling of 21636370 in words is "twenty-one million, six hundred thirty-six thousand, three hundred seventy".