20501155 has 4 divisors (see below), whose sum is σ = 24601392. Its totient is φ = 16400920.

The previous prime is 20501141. The next prime is 20501183. The reversal of 20501155 is 55110502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55110502 = 2 ⋅27555251.

It is not a de Polignac number, because 20501155 - 2⁵ = 20501123 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2050111 + ... + 2050120.

It is an arithmetic number, because the mean of its divisors is an integer number (6150348).

Almost surely, 2^20501155 is an apocalyptic number.

20501155 is a deficient number, since it is larger than the sum of its proper divisors (4100237).

20501155 is an equidigital number, since it uses as much as digits as its factorization.

20501155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4100236.

The product of its (nonzero) digits is 250, while the sum is 19.

The square root of 20501155 is about 4527.8201156848. The cubic root of 20501155 is about 273.6903235846.

Adding to 20501155 its reverse (55110502), we get a palindrome (75611657).

The spelling of 20501155 in words is "twenty million, five hundred one thousand, one hundred fifty-five".