20956217 has 4 divisors (see below), whose sum is σ = 21632256. Its totient is φ = 20280180.

The previous prime is 20956211. The next prime is 20956261. The reversal of 20956217 is 71265902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20956217 - 2⁶ = 20956153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20956211) 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, 337973 + ... + 338034.

It is an arithmetic number, because the mean of its divisors is an integer number (5408064).

Almost surely, 2^20956217 is an apocalyptic number.

It is an amenable number.

20956217 is a deficient number, since it is larger than the sum of its proper divisors (676039).

20956217 is an equidigital number, since it uses as much as digits as its factorization.

20956217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676038.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 20956217 is about 4577.7960854542. The cubic root of 20956217 is about 275.7005477610.

The spelling of 20956217 in words is "twenty million, nine hundred fifty-six thousand, two hundred seventeen".