20409679 has 2 divisors, whose sum is σ = 20409680. Its totient is φ = 20409678.

The previous prime is 20409643. The next prime is 20409689. The reversal of 20409679 is 97690402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20409679 - 2¹¹ = 20407631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20409689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10204839 + 10204840.

It is an arithmetic number, because the mean of its divisors is an integer number (10204840).

Almost surely, 2^20409679 is an apocalyptic number.

20409679 is a deficient number, since it is larger than the sum of its proper divisors (1).

20409679 is an equidigital number, since it uses as much as digits as its factorization.

20409679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 37.

The square root of 20409679 is about 4517.7072725001. The cubic root of 20409679 is about 273.2826485768.

The spelling of 20409679 in words is "twenty million, four hundred nine thousand, six hundred seventy-nine".