1691605644 has 48 divisors (see below), whose sum is σ = 4288865280. Its totient is φ = 516957120.

The previous prime is 1691605639. The next prime is 1691605649. The reversal of 1691605644 is 4465061961.

1691605644 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (1691605639) and next prime (1691605649).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1691605596 and 1691605605.

It is not an unprimeable number, because it can be changed into a prime (1691605649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112599 + ... + 126734.

It is an arithmetic number, because the mean of its divisors is an integer number (89351360).

Almost surely, 2^1691605644 is an apocalyptic number.

It is an amenable number.

1691605644 is an abundant number, since it is smaller than the sum of its proper divisors (2597259636).

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

1691605644 is a wasteful number, since it uses less digits than its factorization.

1691605644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239390 (or 239388 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 1691605644 is about 41129.1337618482. The cubic root of 1691605644 is about 1191.5155334591.

The spelling of 1691605644 in words is "one billion, six hundred ninety-one million, six hundred five thousand, six hundred forty-four".