20505501 has 8 divisors (see below), whose sum is σ = 30378560. Its totient is φ = 13670316.

The previous prime is 20505497. The next prime is 20505571. The reversal of 20505501 is 10550502.

It is not a de Polignac number, because 20505501 - 2² = 20505497 is a prime.

It is a super-2 number, since 2×20505501² = 840951142522002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20505571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 379705 + ... + 379758.

It is an arithmetic number, because the mean of its divisors is an integer number (3797320).

Almost surely, 2^20505501 is an apocalyptic number.

It is an amenable number.

20505501 is a deficient number, since it is larger than the sum of its proper divisors (9873059).

20505501 is an equidigital number, since it uses as much as digits as its factorization.

20505501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759472 (or 759466 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

The square root of 20505501 is about 4528.3000121458. The cubic root of 20505501 is about 273.7096619115.

It can be divided in two parts, 20 and 505501, that added together give a square (505521 = 711²).

The spelling of 20505501 in words is "twenty million, five hundred five thousand, five hundred one".