20871961 has 8 divisors (see below), whose sum is σ = 22834944. Its totient is φ = 18919920.

The previous prime is 20871923. The next prime is 20871973. The reversal of 20871961 is 16917802.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20871961 - 2⁹ = 20871449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20871161) 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, 1560 + ... + 6646.

It is an arithmetic number, because the mean of its divisors is an integer number (2854368).

Almost surely, 2^20871961 is an apocalyptic number.

It is an amenable number.

20871961 is a deficient number, since it is larger than the sum of its proper divisors (1962983).

20871961 is a wasteful number, since it uses less digits than its factorization.

20871961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5471.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20871961 is about 4568.5841351561. The cubic root of 20871961 is about 275.3305600712.

The spelling of 20871961 in words is "twenty million, eight hundred seventy-one thousand, nine hundred sixty-one".