1985615549 has 4 divisors (see below), whose sum is σ = 2012815836. Its totient is φ = 1958415264.

The previous prime is 1985615537. The next prime is 1985615561. The reversal of 1985615549 is 9455165891.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1985615537) and next prime (1985615561).

It can be written as a sum of positive squares in 2 ways, for example, as 360316324 + 1625299225 = 18982^2 + 40315^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985615549 - 2¹⁶ = 1985550013 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1985615549.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1985615509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13600034 + ... + 13600179.

It is an arithmetic number, because the mean of its divisors is an integer number (503203959).

Almost surely, 2^1985615549 is an apocalyptic number.

It is an amenable number.

1985615549 is a deficient number, since it is larger than the sum of its proper divisors (27200287).

1985615549 is an equidigital number, since it uses as much as digits as its factorization.

1985615549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27200286.

The product of its digits is 1944000, while the sum is 53.

The square root of 1985615549 is about 44560.2462852260. The cubic root of 1985615549 is about 1256.8932339051.

The spelling of 1985615549 in words is "one billion, nine hundred eighty-five million, six hundred fifteen thousand, five hundred forty-nine".