21161505 has 8 divisors (see below), whose sum is σ = 33858432. Its totient is φ = 11286128.

The previous prime is 21161501. The next prime is 21161507. The reversal of 21161505 is 50516112.

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 21161505 - 2² = 21161501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21161501) 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, 705369 + ... + 705398.

It is an arithmetic number, because the mean of its divisors is an integer number (4232304).

Almost surely, 2^21161505 is an apocalyptic number.

It is an amenable number.

21161505 is a deficient number, since it is larger than the sum of its proper divisors (12696927).

21161505 is a wasteful number, since it uses less digits than its factorization.

21161505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1410775.

The product of its (nonzero) digits is 300, while the sum is 21.

The square root of 21161505 is about 4600.1635840479. The cubic root of 21161505 is about 276.5978821277.

Adding to 21161505 its reverse (50516112), we get a palindrome (71677617).

It can be divided in two parts, 211 and 61505, that added together give a palindrome (61716).

The spelling of 21161505 in words is "twenty-one million, one hundred sixty-one thousand, five hundred five".