21625117 has 2 divisors, whose sum is σ = 21625118. Its totient is φ = 21625116.

The previous prime is 21625111. The next prime is 21625181. The reversal of 21625117 is 71152612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19131876 + 2493241 = 4374^2 + 1579^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21625117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21625091 and 21625100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21625111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10812558 + 10812559.

It is an arithmetic number, because the mean of its divisors is an integer number (10812559).

Almost surely, 2^21625117 is an apocalyptic number.

It is an amenable number.

21625117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21625117 is an equidigital number, since it uses as much as digits as its factorization.

21625117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 21625117 is about 4650.2813893355. The cubic root of 21625117 is about 278.6032352274.

Adding to 21625117 its reverse (71152612), we get a palindrome (92777729).

It can be divided in two parts, 21625 and 117, that multiplied together give a triangular number (2530125 = T₂₂₄₉).

The spelling of 21625117 in words is "twenty-one million, six hundred twenty-five thousand, one hundred seventeen".