7557356921 has 2 divisors, whose sum is σ = 7557356922. Its totient is φ = 7557356920.

The previous prime is 7557356899. The next prime is 7557356927. The reversal of 7557356921 is 1296537557.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5018305600 + 2539051321 = 70840^2 + 50389^2 .

It is a cyclic number.

It is not a de Polignac number, because 7557356921 - 2¹⁸ = 7557094777 is a prime.

It is a super-2 number, since 2×7557356921² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7557356921.

It is not a weakly prime, because it can be changed into another prime (7557356927) 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, 3778678460 + 3778678461.

It is an arithmetic number, because the mean of its divisors is an integer number (3778678461).

Almost surely, 2^7557356921 is an apocalyptic number.

It is an amenable number.

7557356921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7557356921 is an equidigital number, since it uses as much as digits as its factorization.

7557356921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1984500, while the sum is 50.

The square root of 7557356921 is about 86933.0600002094. The cubic root of 7557356921 is about 1962.4110375836.

The spelling of 7557356921 in words is "seven billion, five hundred fifty-seven million, three hundred fifty-six thousand, nine hundred twenty-one".