1669999661 has 16 divisors (see below), whose sum is σ = 1950220800. Its totient is φ = 1413889200.

The previous prime is 1669999633. The next prime is 1669999679.

1669999661 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 1669999661 - 2¹⁴ = 1669983277 is a prime.

It is a super-2 number, since 2×1669999661² = 5577797735480229842, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1669999594 and 1669999603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1669999601) 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, 55385 + ... + 80046.

It is an arithmetic number, because the mean of its divisors is an integer number (121888800).

Almost surely, 2^1669999661 is an apocalyptic number.

1669999661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1669999661 is a deficient number, since it is larger than the sum of its proper divisors (280221139).

1669999661 is a wasteful number, since it uses less digits than its factorization.

1669999661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135520.

The product of its digits is 8503056, while the sum is 62.

The square root of 1669999661 is about 40865.6293356654. The cubic root of 1669999661 is about 1186.4209155898.

The spelling of 1669999661 in words is "one billion, six hundred sixty-nine million, nine hundred ninety-nine thousand, six hundred sixty-one".