1605939840 has 96 divisors (see below), whose sum is σ = 5545530900. Its totient is φ = 428249088.

The previous prime is 1605939809. The next prime is 1605939871. The reversal of 1605939840 is 489395061.

It is a happy number.

1605939840 is a `hidden beast` number, since 1 + 605 + 9 + 39 + 8 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1605939809) and next prime (1605939871).

It can be written as a sum of positive squares in 2 ways, for example, as 1454354496 + 151585344 = 38136^2 + 12312^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 133645 + ... + 145164.

Almost surely, 2^1605939840 is an apocalyptic number.

1605939840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1605939840 is an abundant number, since it is smaller than the sum of its proper divisors (3939591060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1605939840 is a wasteful number, since it uses less digits than its factorization.

1605939840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278834 (or 278819 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 1605939840 is about 40074.1792180451. The cubic root of 1605939840 is about 1171.0526577164.

The spelling of 1605939840 in words is "one billion, six hundred five million, nine hundred thirty-nine thousand, eight hundred forty".