661629 has 4 divisors (see below), whose sum is σ = 882176. Its totient is φ = 441084.

The previous prime is 661621. The next prime is 661663. The reversal of 661629 is 926166.

661629 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 661629 - 2³ = 661621 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661596 and 661605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110269 + ... + 110274.

It is an arithmetic number, because the mean of its divisors is an integer number (220544).

2⁶⁶¹⁶²⁹ is an apocalyptic number.

It is an amenable number.

661629 is a deficient number, since it is larger than the sum of its proper divisors (220547).

661629 is a wasteful number, since it uses less digits than its factorization.

661629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220546.

The product of its digits is 3888, while the sum is 30.

The square root of 661629 is about 813.4058027824. The cubic root of 661629 is about 87.1374495307.

The spelling of 661629 in words is "six hundred sixty-one thousand, six hundred twenty-nine".