20131961 has 8 divisors (see below), whose sum is σ = 21366504. Its totient is φ = 18903040.

The previous prime is 20131939. The next prime is 20131981. The reversal of 20131961 is 16913102.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 7458361 + 12673600 = 2731^2 + 3560^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20131961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20131931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7721 + ... + 9993.

It is an arithmetic number, because the mean of its divisors is an integer number (2670813).

Almost surely, 2^20131961 is an apocalyptic number.

It is an amenable number.

20131961 is a deficient number, since it is larger than the sum of its proper divisors (1234543).

20131961 is a wasteful number, since it uses less digits than its factorization.

20131961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2811.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 20131961 is about 4486.8653868820. The cubic root of 20131961 is about 272.0374488879.

It can be divided in two parts, 2013 and 1961, that multiplied together give a palindrome (3947493).

The spelling of 20131961 in words is "twenty million, one hundred thirty-one thousand, nine hundred sixty-one".