20621693 has 2 divisors, whose sum is σ = 20621694. Its totient is φ = 20621692.

The previous prime is 20621683. The next prime is 20621759. The reversal of 20621693 is 39612602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15155449 + 5466244 = 3893^2 + 2338^2 .

It is a cyclic number.

It is not a de Polignac number, because 20621693 - 2⁴ = 20621677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20621683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10310846 + 10310847.

It is an arithmetic number, because the mean of its divisors is an integer number (10310847).

Almost surely, 2^20621693 is an apocalyptic number.

It is an amenable number.

20621693 is a deficient number, since it is larger than the sum of its proper divisors (1).

20621693 is an equidigital number, since it uses as much as digits as its factorization.

20621693 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 20621693 is about 4541.1114278335. Note that the first 3 decimals coincide. The cubic root of 20621693 is about 274.2256696622.

The spelling of 20621693 in words is "twenty million, six hundred twenty-one thousand, six hundred ninety-three".