20693639 has 2 divisors, whose sum is σ = 20693640. Its totient is φ = 20693638.

The previous prime is 20693609. The next prime is 20693663. The reversal of 20693639 is 93639602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20693639 - 2¹⁶ = 20628103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20693609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10346819 + 10346820.

It is an arithmetic number, because the mean of its divisors is an integer number (10346820).

Almost surely, 2^20693639 is an apocalyptic number.

20693639 is a deficient number, since it is larger than the sum of its proper divisors (1).

20693639 is an equidigital number, since it uses as much as digits as its factorization.

20693639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 38.

The square root of 20693639 is about 4549.0261595203. The cubic root of 20693639 is about 274.5442102729.

The spelling of 20693639 in words is "twenty million, six hundred ninety-three thousand, six hundred thirty-nine".