1691599481 has 12 divisors (see below), whose sum is σ = 2002391076. Its totient is φ = 1419522720.

The previous prime is 1691599477. The next prime is 1691599499. The reversal of 1691599481 is 1849951961.

It can be written as a sum of positive squares in 2 ways, for example, as 1048723456 + 642876025 = 32384^2 + 25355^2 .

It is not a de Polignac number, because 1691599481 - 2² = 1691599477 is a prime.

It is a super-2 number, since 2×1691599481² = 5723017608238938722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1691599421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 536126 + ... + 539271.

It is an arithmetic number, because the mean of its divisors is an integer number (166865923).

Almost surely, 2^1691599481 is an apocalyptic number.

1691599481 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1691599481 is a deficient number, since it is larger than the sum of its proper divisors (310791595).

1691599481 is a wasteful number, since it uses less digits than its factorization.

1691599481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1075432 (or 1075421 counting only the distinct ones).

The product of its digits is 699840, while the sum is 53.

The square root of 1691599481 is about 41129.0588392197. The cubic root of 1691599481 is about 1191.5140864475.

The spelling of 1691599481 in words is "one billion, six hundred ninety-one million, five hundred ninety-nine thousand, four hundred eighty-one".