1691380644 has 12 divisors (see below), whose sum is σ = 3946554864. Its totient is φ = 563793544.

The previous prime is 1691380637. The next prime is 1691380651. The reversal of 1691380644 is 4460831961.

It is an interprime number because it is at equal distance from previous prime (1691380637) and next prime (1691380651).

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 1691380596 and 1691380605.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70474182 + ... + 70474205.

It is an arithmetic number, because the mean of its divisors is an integer number (328879572).

Almost surely, 2^1691380644 is an apocalyptic number.

It is an amenable number.

1691380644 is an abundant number, since it is smaller than the sum of its proper divisors (2255174220).

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

1691380644 is a wasteful number, since it uses less digits than its factorization.

1691380644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140948394 (or 140948392 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 1691380644 is about 41126.3983835200. The cubic root of 1691380644 is about 1191.4627033993.

The spelling of 1691380644 in words is "one billion, six hundred ninety-one million, three hundred eighty thousand, six hundred forty-four".