75451721 has 2 divisors, whose sum is σ = 75451722. Its totient is φ = 75451720.

The previous prime is 75451711. The next prime is 75451751. The reversal of 75451721 is 12715457.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61011721 + 14440000 = 7811^2 + 3800^2 .

It is a cyclic number.

It is not a de Polignac number, because 75451721 - 2⁶ = 75451657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (75451711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37725860 + 37725861.

It is an arithmetic number, because the mean of its divisors is an integer number (37725861).

Almost surely, 2^75451721 is an apocalyptic number.

It is an amenable number.

75451721 is a deficient number, since it is larger than the sum of its proper divisors (1).

75451721 is an equidigital number, since it uses as much as digits as its factorization.

75451721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9800, while the sum is 32.

The square root of 75451721 is about 8686.2950099568. The cubic root of 75451721 is about 422.5612968498.

The spelling of 75451721 in words is "seventy-five million, four hundred fifty-one thousand, seven hundred twenty-one".