20961947 has 8 divisors (see below), whose sum is σ = 22407840. Its totient is φ = 19560640.

The previous prime is 20961937. The next prime is 20961961. The reversal of 20961947 is 74916902.

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 20961947 - 2¹⁰ = 20960923 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20961947.

It is not an unprimeable number, because it can be changed into a prime (20961907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10172 + ... + 12057.

It is an arithmetic number, because the mean of its divisors is an integer number (2800980).

Almost surely, 2^20961947 is an apocalyptic number.

20961947 is a deficient number, since it is larger than the sum of its proper divisors (1445893).

20961947 is a wasteful number, since it uses less digits than its factorization.

20961947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22293.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 20961947 is about 4578.4218896908. The cubic root of 20961947 is about 275.7256734819.

The spelling of 20961947 in words is "twenty million, nine hundred sixty-one thousand, nine hundred forty-seven".