16172621 has 2 divisors, whose sum is σ = 16172622. Its totient is φ = 16172620.

The previous prime is 16172617. The next prime is 16172623. The reversal of 16172621 is 12627161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12524521 + 3648100 = 3539^2 + 1910^2 .

It is a cyclic number.

It is not a de Polignac number, because 16172621 - 2² = 16172617 is a prime.

Together with 16172623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16172623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8086310 + 8086311.

It is an arithmetic number, because the mean of its divisors is an integer number (8086311).

Almost surely, 2^16172621 is an apocalyptic number.

It is an amenable number.

16172621 is a deficient number, since it is larger than the sum of its proper divisors (1).

16172621 is an equidigital number, since it uses as much as digits as its factorization.

16172621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 26.

The square root of 16172621 is about 4021.5197376116. The cubic root of 16172621 is about 252.8871738848.

Adding to 16172621 its reverse (12627161), we get a palindrome (28799782).

The spelling of 16172621 in words is "sixteen million, one hundred seventy-two thousand, six hundred twenty-one".