1691601408 has 200 divisors, whose sum is σ = 5771258592. Its totient is φ = 483231744.

The previous prime is 1691601323. The next prime is 1691601421. The reversal of 1691601408 is 8041061961.

It is a happy number.

1691601408 is a `hidden beast` number, since 1 + 6 + 9 + 1 + 601 + 40 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 287391 + ... + 293217.

Almost surely, 2^1691601408 is an apocalyptic number.

1691601408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1691601408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2885629296).

1691601408 is an abundant number, since it is smaller than the sum of its proper divisors (4079657184).

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

1691601408 is an frugal number, since it uses more digits than its factorization.

1691601408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5864 (or 5839 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1691601408 is about 41129.0822654724. The cubic root of 1691601408 is about 1191.5145388884.

The spelling of 1691601408 in words is "one billion, six hundred ninety-one million, six hundred one thousand, four hundred eight".