7157221021 has 2 divisors, whose sum is σ = 7157221022. Its totient is φ = 7157221020.

The previous prime is 7157220997. The next prime is 7157221033. The reversal of 7157221021 is 1201227517.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7099916121 + 57304900 = 84261^2 + 7570^2 .

It is a cyclic number.

It is not a de Polignac number, because 7157221021 - 2⁵ = 7157220989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7157221081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3578610510 + 3578610511.

It is an arithmetic number, because the mean of its divisors is an integer number (3578610511).

Almost surely, 2^7157221021 is an apocalyptic number.

It is an amenable number.

7157221021 is a deficient number, since it is larger than the sum of its proper divisors (1).

7157221021 is an equidigital number, since it uses as much as digits as its factorization.

7157221021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1960, while the sum is 28.

The square root of 7157221021 is about 84600.3606434393. The cubic root of 7157221021 is about 1927.1468505600.

Adding to 7157221021 its reverse (1201227517), we get a palindrome (8358448538).

The spelling of 7157221021 in words is "seven billion, one hundred fifty-seven million, two hundred twenty-one thousand, twenty-one".