21071465 has 4 divisors (see below), whose sum is σ = 25285764. Its totient is φ = 16857168.

The previous prime is 21071461. The next prime is 21071467. The reversal of 21071465 is 56417012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8082649 + 12988816 = 2843^2 + 3604^2 .

It is a cyclic number.

It is not a de Polignac number, because 21071465 - 2² = 21071461 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21071461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2107142 + ... + 2107151.

It is an arithmetic number, because the mean of its divisors is an integer number (6321441).

Almost surely, 2^21071465 is an apocalyptic number.

It is an amenable number.

21071465 is a deficient number, since it is larger than the sum of its proper divisors (4214299).

21071465 is an equidigital number, since it uses as much as digits as its factorization.

21071465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214298.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21071465 is about 4590.3665430987. The cubic root of 21071465 is about 276.2050260180.

Adding to 21071465 its reverse (56417012), we get a palindrome (77488477).

The spelling of 21071465 in words is "twenty-one million, seventy-one thousand, four hundred sixty-five".