20628657 has 36 divisors (see below), whose sum is σ = 35879220. Its totient is φ = 11374272.

The previous prime is 20628653. The next prime is 20628659. The reversal of 20628657 is 75682602.

20628657 is a `hidden beast` number, since 20 + 628 + 6 + 5 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11861136 + 8767521 = 3444^2 + 2961^2 .

It is not a de Polignac number, because 20628657 - 2² = 20628653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20628653) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11983 + ... + 13595.

It is an arithmetic number, because the mean of its divisors is an integer number (996645).

Almost surely, 2^20628657 is an apocalyptic number.

It is an amenable number.

20628657 is a deficient number, since it is larger than the sum of its proper divisors (15250563).

20628657 is a wasteful number, since it uses less digits than its factorization.

20628657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662 (or 1652 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 20628657 is about 4541.8781357496. The cubic root of 20628657 is about 274.2565350982.

The spelling of 20628657 in words is "twenty million, six hundred twenty-eight thousand, six hundred fifty-seven".