642961 has 4 divisors (see below), whose sum is σ = 701424. Its totient is φ = 584500.

The previous prime is 642953. The next prime is 642973. The reversal of 642961 is 169246.

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 a cyclic number.

It is not a de Polignac number, because 642961 - 2³ = 642953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642931) 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, 29215 + ... + 29236.

It is an arithmetic number, because the mean of its divisors is an integer number (175356).

2⁶⁴²⁹⁶¹ is an apocalyptic number.

It is an amenable number.

642961 is a deficient number, since it is larger than the sum of its proper divisors (58463).

642961 is a wasteful number, since it uses less digits than its factorization.

642961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58462.

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

The square root of 642961 is about 801.8484894293. The cubic root of 642961 is about 86.3100848571.

It can be divided in two parts, 64 and 2961, that added together give a square (3025 = 55²).

The spelling of 642961 in words is "six hundred forty-two thousand, nine hundred sixty-one".