661429 has 4 divisors (see below), whose sum is σ = 663084. Its totient is φ = 659776.

The previous prime is 661421. The next prime is 661439. The reversal of 661429 is 924166.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 643204 + 18225 = 802^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 661429 - 2³ = 661421 is a prime.

It is a Duffinian number.

661429 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 661397 and 661406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 189 + ... + 1165.

It is an arithmetic number, because the mean of its divisors is an integer number (165771).

2⁶⁶¹⁴²⁹ is an apocalyptic number.

It is an amenable number.

661429 is a deficient number, since it is larger than the sum of its proper divisors (1655).

661429 is an equidigital number, since it uses as much as digits as its factorization.

661429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1654.

The product of its digits is 2592, while the sum is 28.

The square root of 661429 is about 813.2828536247. The cubic root of 661429 is about 87.1286685541.

The spelling of 661429 in words is "six hundred sixty-one thousand, four hundred twenty-nine".