961621 has 4 divisors (see below), whose sum is σ = 971244. Its totient is φ = 952000.

The previous prime is 961619. The next prime is 961627. The reversal of 961621 is 126169.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126169 = 281 ⋅449.

It can be written as a sum of positive squares in 2 ways, for example, as 722500 + 239121 = 850^2 + 489^2 .

It is a cyclic number.

It is not a de Polignac number, because 961621 - 2¹ = 961619 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (961627) 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, 4660 + ... + 4861.

It is an arithmetic number, because the mean of its divisors is an integer number (242811).

2⁹⁶¹⁶²¹ is an apocalyptic number.

It is an amenable number.

961621 is a deficient number, since it is larger than the sum of its proper divisors (9623).

961621 is a wasteful number, since it uses less digits than its factorization.

961621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9622.

The product of its digits is 648, while the sum is 25.

The square root of 961621 is about 980.6227613104. The cubic root of 961621 is about 98.7039757756.

Adding to 961621 its product of digits (648), we get a palindrome (962269).

The spelling of 961621 in words is "nine hundred sixty-one thousand, six hundred twenty-one".