20628138 has 8 divisors (see below), whose sum is σ = 41256288. Its totient is φ = 6876044.

The previous prime is 20628137. The next prime is 20628143. The reversal of 20628138 is 83182602.

It is a sphenic number, since it is the product of 3 distinct primes.

20628138 is an admirable number.

It is a super-3 number, since 3×20628138³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20628137) 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, 1719006 + ... + 1719017.

It is an arithmetic number, because the mean of its divisors is an integer number (5157036).

Almost surely, 2^20628138 is an apocalyptic number.

20628138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20628138 is a wasteful number, since it uses less digits than its factorization.

20628138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3438028.

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 20628138 is about 4541.8210004358. The cubic root of 20628138 is about 274.2542350561.

The spelling of 20628138 in words is "twenty million, six hundred twenty-eight thousand, one hundred thirty-eight".