20621759 has 2 divisors, whose sum is σ = 20621760. Its totient is φ = 20621758.

The previous prime is 20621693. The next prime is 20621771. The reversal of 20621759 is 95712602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20621759 - 2¹⁶ = 20556223 is a prime.

It is a Sophie Germain 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 (20621959) 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, 10310879 + 10310880.

It is an arithmetic number, because the mean of its divisors is an integer number (10310880).

Almost surely, 2^20621759 is an apocalyptic number.

20621759 is a deficient number, since it is larger than the sum of its proper divisors (1).

20621759 is an equidigital number, since it uses as much as digits as its factorization.

20621759 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 20621759 is about 4541.1186947711. The cubic root of 20621759 is about 274.2259622162.

The spelling of 20621759 in words is "twenty million, six hundred twenty-one thousand, seven hundred fifty-nine".