21161506 has 8 divisors (see below), whose sum is σ = 31863744. Its totient is φ = 10540260.

The previous prime is 21161501. The next prime is 21161507. The reversal of 21161506 is 60516112.

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

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 3 ways as a sum of consecutive naturals, for example, 19590 + ... + 20641.

It is an arithmetic number, because the mean of its divisors is an integer number (3982968).

Almost surely, 2^21161506 is an apocalyptic number.

21161506 is a deficient number, since it is larger than the sum of its proper divisors (10702238).

21161506 is a wasteful number, since it uses less digits than its factorization.

21161506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40496.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21161506 is about 4600.1636927396. The cubic root of 21161506 is about 276.5978864847.

Adding to 21161506 its reverse (60516112), we get a palindrome (81677618).

The spelling of 21161506 in words is "twenty-one million, one hundred sixty-one thousand, five hundred six".