21625161 has 8 divisors (see below), whose sum is σ = 28864224. Its totient is φ = 14401440.

The previous prime is 21625117. The next prime is 21625181. The reversal of 21625161 is 16152612.

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

It is not a de Polignac number, because 21625161 - 2⁷ = 21625033 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21625111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6 + ... + 6576.

It is an arithmetic number, because the mean of its divisors is an integer number (3608028).

Almost surely, 2^21625161 is an apocalyptic number.

It is an amenable number.

21625161 is a deficient number, since it is larger than the sum of its proper divisors (7239063).

21625161 is a wasteful number, since it uses less digits than its factorization.

21625161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7671.

The product of its digits is 720, while the sum is 24.

The square root of 21625161 is about 4650.2861202296. The cubic root of 21625161 is about 278.6034241826.

Adding to 21625161 its reverse (16152612), we get a palindrome (37777773).

The spelling of 21625161 in words is "twenty-one million, six hundred twenty-five thousand, one hundred sixty-one".