20956661 has 8 divisors (see below), whose sum is σ = 22923648. Its totient is φ = 19000000.

The previous prime is 20956643. The next prime is 20956669. The reversal of 20956661 is 16665902.

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 20956661 - 2¹⁸ = 20694517 is a prime.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20956669) 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, 2036 + ... + 6786.

It is an arithmetic number, because the mean of its divisors is an integer number (2865456).

Almost surely, 2^20956661 is an apocalyptic number.

It is an amenable number.

20956661 is a deficient number, since it is larger than the sum of its proper divisors (1966987).

20956661 is a wasteful number, since it uses less digits than its factorization.

20956661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5163.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 20956661 is about 4577.8445801490. The cubic root of 20956661 is about 275.7024948392.

The spelling of 20956661 in words is "twenty million, nine hundred fifty-six thousand, six hundred sixty-one".