20155145 has 16 divisors (see below), whose sum is σ = 25295760. Its totient is φ = 15396864.

The previous prime is 20155129. The next prime is 20155147. The reversal of 20155145 is 54155102.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 183184 + 19971961 = 428^2 + 4469^2 .

It is a cyclic number.

It is not a de Polignac number, because 20155145 - 2⁴ = 20155129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20155145.

It is not an unprimeable number, because it can be changed into a prime (20155147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13349 + ... + 14781.

It is an arithmetic number, because the mean of its divisors is an integer number (1580985).

Almost surely, 2^20155145 is an apocalyptic number.

It is an amenable number.

20155145 is a deficient number, since it is larger than the sum of its proper divisors (5140615).

20155145 is a wasteful number, since it uses less digits than its factorization.

20155145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1564.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 20155145 is about 4489.4481843541. The cubic root of 20155145 is about 272.1418350883.

The spelling of 20155145 in words is "twenty million, one hundred fifty-five thousand, one hundred forty-five".