20720655 has 48 divisors (see below), whose sum is σ = 37425024. Its totient is φ = 10598400.

The previous prime is 20720653. The next prime is 20720681. The reversal of 20720655 is 55602702.

20720655 is a `hidden beast` number, since 2 + 0 + 7 + 2 + 0 + 655 = 666.

It is not a de Polignac number, because 20720655 - 2¹ = 20720653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720653) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 205105 + ... + 205205.

It is an arithmetic number, because the mean of its divisors is an integer number (779688).

Almost surely, 2^20720655 is an apocalyptic number.

20720655 is a deficient number, since it is larger than the sum of its proper divisors (16704369).

20720655 is a wasteful number, since it uses less digits than its factorization.

20720655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 20720655 is about 4551.9946177473. The cubic root of 20720655 is about 274.6636328162.

The spelling of 20720655 in words is "twenty million, seven hundred twenty thousand, six hundred fifty-five".