21148665 has 16 divisors (see below), whose sum is σ = 34930176. Its totient is φ = 10915200.

The previous prime is 21148601. The next prime is 21148667. The reversal of 21148665 is 56684112.

It is not a de Polignac number, because 21148665 - 2⁶ = 21148601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21148667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22276 + ... + 23205.

It is an arithmetic number, because the mean of its divisors is an integer number (2183136).

Almost surely, 2^21148665 is an apocalyptic number.

It is an amenable number.

21148665 is a deficient number, since it is larger than the sum of its proper divisors (13781511).

21148665 is a wasteful number, since it uses less digits than its factorization.

21148665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45520.

The product of its digits is 11520, while the sum is 33.

The square root of 21148665 is about 4598.7677697401. The cubic root of 21148665 is about 276.5419277685.

The spelling of 21148665 in words is "twenty-one million, one hundred forty-eight thousand, six hundred sixty-five".