21206364 has 24 divisors (see below), whose sum is σ = 49974288. Its totient is φ = 6998400.

The previous prime is 21206363. The next prime is 21206377. The reversal of 21206364 is 46360212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21206363) 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, 7537 + ... + 9960.

It is an arithmetic number, because the mean of its divisors is an integer number (2082262).

Almost surely, 2^21206364 is an apocalyptic number.

It is an amenable number.

21206364 is an abundant number, since it is smaller than the sum of its proper divisors (28767924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21206364 is a wasteful number, since it uses less digits than its factorization.

21206364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17605 (or 17603 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 21206364 is about 4605.0368076705. The cubic root of 21206364 is about 276.7931919149.

Adding to 21206364 its reverse (46360212), we get a palindrome (67566576).

The spelling of 21206364 in words is "twenty-one million, two hundred six thousand, three hundred sixty-four".