20155521 has 16 divisors (see below), whose sum is σ = 28523520. Its totient is φ = 12632400.

The previous prime is 20155511. The next prime is 20155547. The reversal of 20155521 is 12555102.

It is not a de Polignac number, because 20155521 - 2¹¹ = 20153473 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20155501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1596 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (1782720).

Almost surely, 2^20155521 is an apocalyptic number.

It is an amenable number.

20155521 is a deficient number, since it is larger than the sum of its proper divisors (8367999).

20155521 is a wasteful number, since it uses less digits than its factorization.

20155521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5036.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 20155521 is about 4489.4900601293. The cubic root of 20155521 is about 272.1435273724.

The spelling of 20155521 in words is "twenty million, one hundred fifty-five thousand, five hundred twenty-one".