1691661961 has 8 divisors (see below), whose sum is σ = 1846142784. Its totient is φ = 1537296720.

The previous prime is 1691661931. The next prime is 1691661967.

It is a happy number.

1691661961 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1691661961 - 2¹⁵ = 1691629193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1691661967) 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, 3276 + ... + 58258.

It is an arithmetic number, because the mean of its divisors is an integer number (230767848).

Almost surely, 2^1691661961 is an apocalyptic number.

1691661961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1691661961 is a deficient number, since it is larger than the sum of its proper divisors (154480823).

1691661961 is a wasteful number, since it uses less digits than its factorization.

1691661961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57791.

The product of its digits is 104976, while the sum is 46.

The square root of 1691661961 is about 41129.8183924996. The cubic root of 1691661961 is about 1191.5287559727.

The spelling of 1691661961 in words is "one billion, six hundred ninety-one million, six hundred sixty-one thousand, nine hundred sixty-one".