20628381 has 8 divisors (see below), whose sum is σ = 27530784. Its totient is φ = 13739120.

The previous prime is 20628379. The next prime is 20628397. The reversal of 20628381 is 18382602.

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

It is a cyclic number.

It is not a de Polignac number, because 20628381 - 2¹ = 20628379 is a prime.

It is a super-3 number, since 3×20628381³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20628481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1291 + ... + 6551.

It is an arithmetic number, because the mean of its divisors is an integer number (3441348).

Almost surely, 2^20628381 is an apocalyptic number.

It is an amenable number.

20628381 is a deficient number, since it is larger than the sum of its proper divisors (6902403).

20628381 is a wasteful number, since it uses less digits than its factorization.

20628381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6571.

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

The square root of 20628381 is about 4541.8477517416. The cubic root of 20628381 is about 274.2553119592.

The spelling of 20628381 in words is "twenty million, six hundred twenty-eight thousand, three hundred eighty-one".