21046505 has 8 divisors (see below), whose sum is σ = 25501632. Its totient is φ = 16673328.

The previous prime is 21046477. The next prime is 21046507. The reversal of 21046505 is 50564012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21046505 - 2¹⁰ = 21045481 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21046507) 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, 19919 + ... + 20948.

It is an arithmetic number, because the mean of its divisors is an integer number (3187704).

Almost surely, 2^21046505 is an apocalyptic number.

It is an amenable number.

21046505 is a deficient number, since it is larger than the sum of its proper divisors (4455127).

21046505 is a wasteful number, since it uses less digits than its factorization.

21046505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40975.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 21046505 is about 4587.6470003696. The cubic root of 21046505 is about 276.0959242644.

The spelling of 21046505 in words is "twenty-one million, forty-six thousand, five hundred five".