20172641 has 2 divisors, whose sum is σ = 20172642. Its totient is φ = 20172640.

The previous prime is 20172637. The next prime is 20172643. The reversal of 20172641 is 14627102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16638241 + 3534400 = 4079^2 + 1880^2 .

It is a cyclic number.

It is not a de Polignac number, because 20172641 - 2² = 20172637 is a prime.

Together with 20172643, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20172643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10086320 + 10086321.

It is an arithmetic number, because the mean of its divisors is an integer number (10086321).

Almost surely, 2^20172641 is an apocalyptic number.

It is an amenable number.

20172641 is a deficient number, since it is larger than the sum of its proper divisors (1).

20172641 is an equidigital number, since it uses as much as digits as its factorization.

20172641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 20172641 is about 4491.3963307640. The cubic root of 20172641 is about 272.2205580227.

Adding to 20172641 its reverse (14627102), we get a palindrome (34799743).

The spelling of 20172641 in words is "twenty million, one hundred seventy-two thousand, six hundred forty-one".