1691947680 has 48 divisors (see below), whose sum is σ = 5329636704. Its totient is φ = 451185920.

The previous prime is 1691947669. The next prime is 1691947687. The reversal of 1691947680 is 867491961.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (1691947687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1761966 + ... + 1762925.

It is an arithmetic number, because the mean of its divisors is an integer number (111034098).

Almost surely, 2^1691947680 is an apocalyptic number.

1691947680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1691947680 is an abundant number, since it is smaller than the sum of its proper divisors (3637689024).

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

1691947680 is a wasteful number, since it uses less digits than its factorization.

1691947680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3524909 (or 3524901 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 51.

The square root of 1691947680 is about 41133.2916261269. The cubic root of 1691947680 is about 1191.5958346301.

The spelling of 1691947680 in words is "one billion, six hundred ninety-one million, nine hundred forty-seven thousand, six hundred eighty".