1975785521 has 2 divisors, whose sum is σ = 1975785522. Its totient is φ = 1975785520.

The previous prime is 1975785503. The next prime is 1975785523. The reversal of 1975785521 is 1255875791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1851150625 + 124634896 = 43025^2 + 11164^2 .

It is an emirp because it is prime and its reverse (1255875791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1975785521 - 2¹⁴ = 1975769137 is a prime.

Together with 1975785523, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1975785521.

It is not a weakly prime, because it can be changed into another prime (1975785523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 987892760 + 987892761.

It is an arithmetic number, because the mean of its divisors is an integer number (987892761).

Almost surely, 2^1975785521 is an apocalyptic number.

It is an amenable number.

1975785521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1975785521 is an equidigital number, since it uses as much as digits as its factorization.

1975785521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 882000, while the sum is 50.

The square root of 1975785521 is about 44449.8090097134. The cubic root of 1975785521 is about 1254.8156681276.

The spelling of 1975785521 in words is "one billion, nine hundred seventy-five million, seven hundred eighty-five thousand, five hundred twenty-one".