20628155 has 4 divisors (see below), whose sum is σ = 24753792. Its totient is φ = 16502520.

The previous prime is 20628151. The next prime is 20628173. The reversal of 20628155 is 55182602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55182602 = 2 ⋅27591301.

It is not a de Polignac number, because 20628155 - 2² = 20628151 is a prime.

It is a super-3 number, since 3×20628155³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20628151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2062811 + ... + 2062820.

It is an arithmetic number, because the mean of its divisors is an integer number (6188448).

Almost surely, 2^20628155 is an apocalyptic number.

20628155 is a deficient number, since it is larger than the sum of its proper divisors (4125637).

20628155 is an equidigital number, since it uses as much as digits as its factorization.

20628155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4125636.

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 20628155 is about 4541.8228719315. The cubic root of 20628155 is about 274.2543103953.

The spelling of 20628155 in words is "twenty million, six hundred twenty-eight thousand, one hundred fifty-five".