905172421 has 2 divisors, whose sum is σ = 905172422. Its totient is φ = 905172420.

The previous prime is 905172311. The next prime is 905172427. The reversal of 905172421 is 124271509.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 585156100 + 320016321 = 24190^2 + 17889^2 .

It is a cyclic number.

It is not a de Polignac number, because 905172421 - 2⁹ = 905171909 is a prime.

It is a super-2 number, since 2×905172421² = 1638674223478002482, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (905172427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 452586210 + 452586211.

It is an arithmetic number, because the mean of its divisors is an integer number (452586211).

Almost surely, 2^905172421 is an apocalyptic number.

It is an amenable number.

905172421 is a deficient number, since it is larger than the sum of its proper divisors (1).

905172421 is an equidigital number, since it uses as much as digits as its factorization.

905172421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 905172421 is about 30086.0835104870. The cubic root of 905172421 is about 967.3354516768.

The spelling of 905172421 in words is "nine hundred five million, one hundred seventy-two thousand, four hundred twenty-one".