20646929 has 2 divisors, whose sum is σ = 20646930. Its totient is φ = 20646928.

The previous prime is 20646877. The next prime is 20646949. The reversal of 20646929 is 92964602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17205904 + 3441025 = 4148^2 + 1855^2 .

It is a cyclic number.

It is not a de Polignac number, because 20646929 - 2¹² = 20642833 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20646892 and 20646901.

It is not a weakly prime, because it can be changed into another prime (20646949) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10323464 + 10323465.

It is an arithmetic number, because the mean of its divisors is an integer number (10323465).

Almost surely, 2^20646929 is an apocalyptic number.

It is an amenable number.

20646929 is a deficient number, since it is larger than the sum of its proper divisors (1).

20646929 is an equidigital number, since it uses as much as digits as its factorization.

20646929 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 20646929 is about 4543.8891931912. The cubic root of 20646929 is about 274.3374861842.

The spelling of 20646929 in words is "twenty million, six hundred forty-six thousand, nine hundred twenty-nine".