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75220721 is a prime number
BaseRepresentation
bin1000111101111…
…00011011110001
312020112121102122
410132330123301
5123224030341
611244124025
71602236252
oct436743361
9166477378
1075220721
1139507494
1221236615
1312778c04
149dc0b29
15690c94b
hex47bc6f1

75220721 has 2 divisors, whose sum is σ = 75220722. Its totient is φ = 75220720.

The previous prime is 75220697. The next prime is 75220777. The reversal of 75220721 is 12702257.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54390625 + 20830096 = 7375^2 + 4564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-75220721 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (75220021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37610360 + 37610361.

It is an arithmetic number, because the mean of its divisors is an integer number (37610361).

Almost surely, 275220721 is an apocalyptic number.

It is an amenable number.

75220721 is a deficient number, since it is larger than the sum of its proper divisors (1).

75220721 is an equidigital number, since it uses as much as digits as its factorization.

75220721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 75220721 is about 8672.9880087545. The cubic root of 75220721 is about 422.1296237096.

Adding to 75220721 its reverse (12702257), we get a palindrome (87922978).

The spelling of 75220721 in words is "seventy-five million, two hundred twenty thousand, seven hundred twenty-one".