21065455 has 16 divisors (see below), whose sum is σ = 26373600. Its totient is φ = 16132480.

The previous prime is 21065453. The next prime is 21065459. The reversal of 21065455 is 55456012.

It is not a de Polignac number, because 21065455 - 2¹ = 21065453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065453) 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, 18441 + ... + 19549.

It is an arithmetic number, because the mean of its divisors is an integer number (1648350).

Almost surely, 2^21065455 is an apocalyptic number.

21065455 is a deficient number, since it is larger than the sum of its proper divisors (5308145).

21065455 is a wasteful number, since it uses less digits than its factorization.

21065455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1274.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 21065455 is about 4589.7118645946. The cubic root of 21065455 is about 276.1787638027.

The spelling of 21065455 in words is "twenty-one million, sixty-five thousand, four hundred fifty-five".