20155549 has 4 divisors (see below), whose sum is σ = 20805760. Its totient is φ = 19505340.

The previous prime is 20155547. The next prime is 20155571. The reversal of 20155549 is 94555102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20155549 - 2¹ = 20155547 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 650179 = 20155549 / (2 + 0 + 1 + 5 + 5 + 5 + 4 + 9).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20155549.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20155547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 325059 + ... + 325120.

It is an arithmetic number, because the mean of its divisors is an integer number (5201440).

Almost surely, 2^20155549 is an apocalyptic number.

It is an amenable number.

20155549 is a deficient number, since it is larger than the sum of its proper divisors (650211).

20155549 is an equidigital number, since it uses as much as digits as its factorization.

20155549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650210.

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 20155549 is about 4489.4931785225. The cubic root of 20155549 is about 272.1436533927.

The spelling of 20155549 in words is "twenty million, one hundred fifty-five thousand, five hundred forty-nine".