21206346 has 32 divisors (see below), whose sum is σ = 48677760. Its totient is φ = 6033216.

The previous prime is 21206323. The next prime is 21206347. The reversal of 21206346 is 64360212.

It is a super-2 number, since 2×21206346² = 899418221343432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21206347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10360 + ... + 12236.

It is an arithmetic number, because the mean of its divisors is an integer number (1521180).

Almost surely, 2^21206346 is an apocalyptic number.

21206346 is an abundant number, since it is smaller than the sum of its proper divisors (27471414).

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

21206346 is a wasteful number, since it uses less digits than its factorization.

21206346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2158.

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

The square root of 21206346 is about 4605.0348532883. The cubic root of 21206346 is about 276.7931136007.

Adding to 21206346 its reverse (64360212), we get a palindrome (85566558).

The spelling of 21206346 in words is "twenty-one million, two hundred six thousand, three hundred forty-six".