669129891 has 8 divisors (see below), whose sum is σ = 892441344. Its totient is φ = 445952520.

The previous prime is 669129889. The next prime is 669129893. The reversal of 669129891 is 198921966.

669129891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (669129889) and next prime (669129893).

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

It is not a de Polignac number, because 669129891 - 2¹ = 669129889 is a prime.

It is a super-2 number, since 2×669129891² = 895469622059343762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (669129893) 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, 21231 + ... + 42296.

It is an arithmetic number, because the mean of its divisors is an integer number (111555168).

Almost surely, 2^669129891 is an apocalyptic number.

669129891 is a deficient number, since it is larger than the sum of its proper divisors (223311453).

669129891 is a wasteful number, since it uses less digits than its factorization.

669129891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67041.

The product of its digits is 419904, while the sum is 51.

The square root of 669129891 is about 25867.5451289835. The cubic root of 669129891 is about 874.6550546719.

The spelling of 669129891 in words is "six hundred sixty-nine million, one hundred twenty-nine thousand, eight hundred ninety-one".