75172621 has 2 divisors, whose sum is σ = 75172622. Its totient is φ = 75172620.

The previous prime is 75172619. The next prime is 75172633. The reversal of 75172621 is 12627157.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75168900 + 3721 = 8670^2 + 61^2 .

It is a cyclic number.

It is not a de Polignac number, because 75172621 - 2¹ = 75172619 is a prime.

Together with 75172619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75170621) 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 as a sum of consecutive naturals, namely, 37586310 + 37586311.

It is an arithmetic number, because the mean of its divisors is an integer number (37586311).

Almost surely, 2^75172621 is an apocalyptic number.

It is an amenable number.

75172621 is a deficient number, since it is larger than the sum of its proper divisors (1).

75172621 is an equidigital number, since it uses as much as digits as its factorization.

75172621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5880, while the sum is 31.

The square root of 75172621 is about 8670.2145878865. The cubic root of 75172621 is about 422.0396273891.

Adding to 75172621 its reverse (12627157), we get a palindrome (87799778).

The spelling of 75172621 in words is "seventy-five million, one hundred seventy-two thousand, six hundred twenty-one".