20005961 has 4 divisors (see below), whose sum is σ = 20037252. Its totient is φ = 19974672.

The previous prime is 20005949. The next prime is 20005981. The reversal of 20005961 is 16950002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12823561 + 7182400 = 3581^2 + 2680^2 .

It is a cyclic number.

It is not a de Polignac number, because 20005961 - 2²² = 15811657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20005981) 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, 14666 + ... + 15971.

It is an arithmetic number, because the mean of its divisors is an integer number (5009313).

Almost surely, 2^20005961 is an apocalyptic number.

It is an amenable number.

20005961 is a deficient number, since it is larger than the sum of its proper divisors (31291).

20005961 is an equidigital number, since it uses as much as digits as its factorization.

20005961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31290.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 20005961 is about 4472.8023654081. The cubic root of 20005961 is about 271.4687267197.

Adding to 20005961 its reverse (16950002), we get a palindrome (36955963).

The spelling of 20005961 in words is "twenty million, five thousand, nine hundred sixty-one".