21445965 has 48 divisors (see below), whose sum is σ = 40622400. Its totient is φ = 10824192.

The previous prime is 21445961. The next prime is 21445981. The reversal of 21445965 is 56954412.

21445965 is a `hidden beast` number, since 21 + 44 + 596 + 5 = 666.

It is not a de Polignac number, because 21445965 - 2² = 21445961 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445961) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22621 + ... + 23549.

It is an arithmetic number, because the mean of its divisors is an integer number (846300).

Almost surely, 2^21445965 is an apocalyptic number.

It is an amenable number.

21445965 is a deficient number, since it is larger than the sum of its proper divisors (19176435).

21445965 is an equidigital number, since it uses as much as digits as its factorization.

21445965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968 (or 956 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 21445965 is about 4630.9788382155. The cubic root of 21445965 is about 277.8317435002.

The spelling of 21445965 in words is "twenty-one million, four hundred forty-five thousand, nine hundred sixty-five".