21641306 has 16 divisors (see below), whose sum is σ = 34468416. Its totient is φ = 10155456.

The previous prime is 21641303. The next prime is 21641309. The reversal of 21641306 is 60314612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21641303) and next prime (21641309).

It is a super-2 number, since 2×21641306² = 936692250771272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21641303) 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 7 ways as a sum of consecutive naturals, for example, 15905 + ... + 17211.

It is an arithmetic number, because the mean of its divisors is an integer number (2154276).

Almost surely, 2^21641306 is an apocalyptic number.

21641306 is a deficient number, since it is larger than the sum of its proper divisors (12827110).

21641306 is a wasteful number, since it uses less digits than its factorization.

21641306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1813.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21641306 is about 4652.0217110413. The cubic root of 21641306 is about 278.6727405583.

Adding to 21641306 its reverse (60314612), we get a palindrome (81955918).

The spelling of 21641306 in words is "twenty-one million, six hundred forty-one thousand, three hundred six".