21320446 has 16 divisors (see below), whose sum is σ = 36612576. Its totient is φ = 9121536.

The previous prime is 21320407. The next prime is 21320447. The reversal of 21320446 is 64402312.

It is a happy number.

It is a super-2 number, since 2×21320446² = 909122835277832, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320447) 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, 11110 + ... + 12886.

It is an arithmetic number, because the mean of its divisors is an integer number (2288286).

Almost surely, 2^21320446 is an apocalyptic number.

21320446 is a deficient number, since it is larger than the sum of its proper divisors (15292130).

21320446 is a wasteful number, since it uses less digits than its factorization.

21320446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21320446 is about 4617.4068480046. The cubic root of 21320446 is about 277.2886511292.

Adding to 21320446 its reverse (64402312), we get a palindrome (85722758).

The spelling of 21320446 in words is "twenty-one million, three hundred twenty thousand, four hundred forty-six".