20723639 has 2 divisors, whose sum is σ = 20723640. Its totient is φ = 20723638.

The previous prime is 20723627. The next prime is 20723669. The reversal of 20723639 is 93632702.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20723639 - 2²⁰ = 19675063 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20723609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10361819 + 10361820.

It is an arithmetic number, because the mean of its divisors is an integer number (10361820).

Almost surely, 2^20723639 is an apocalyptic number.

20723639 is a deficient number, since it is larger than the sum of its proper divisors (1).

20723639 is an equidigital number, since it uses as much as digits as its factorization.

20723639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608, while the sum is 32.

The square root of 20723639 is about 4552.3223743492. The cubic root of 20723639 is about 274.6768170349.

The spelling of 20723639 in words is "twenty million, seven hundred twenty-three thousand, six hundred thirty-nine".