1985473561 has 2 divisors, whose sum is σ = 1985473562. Its totient is φ = 1985473560.

The previous prime is 1985473559. The next prime is 1985473591. The reversal of 1985473561 is 1653745891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1016334400 + 969139161 = 31880^2 + 31131^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985473561 - 2¹ = 1985473559 is a prime.

It is a super-2 number, since 2×1985473561² = 7884210522860041442, which contains 22 as substring.

Together with 1985473559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1985473531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992736780 + 992736781.

It is an arithmetic number, because the mean of its divisors is an integer number (992736781).

Almost surely, 2^1985473561 is an apocalyptic number.

It is an amenable number.

1985473561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985473561 is an equidigital number, since it uses as much as digits as its factorization.

1985473561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 49.

The square root of 1985473561 is about 44558.6530429276. The cubic root of 1985473561 is about 1256.8632737565.

The spelling of 1985473561 in words is "one billion, nine hundred eighty-five million, four hundred seventy-three thousand, five hundred sixty-one".