20871729477 has 24 divisors (see below), whose sum is σ = 31491540288. Its totient is φ = 13295673600.

The previous prime is 20871729469. The next prime is 20871729499. The reversal of 20871729477 is 77492717802.

20871729477 is a `hidden beast` number, since 20 + 87 + 1 + 72 + 9 + 477 = 666.

It is not a de Polignac number, because 20871729477 - 2³ = 20871729469 is a prime.

It is a super-2 number, since 2×20871729477² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20871729407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 149077 + ... + 252917.

It is an arithmetic number, because the mean of its divisors is an integer number (1312147512).

Almost surely, 2^20871729477 is an apocalyptic number.

It is an amenable number.

20871729477 is a deficient number, since it is larger than the sum of its proper divisors (10619810811).

20871729477 is a wasteful number, since it uses less digits than its factorization.

20871729477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104841 (or 104838 counting only the distinct ones).

The product of its (nonzero) digits is 2765952, while the sum is 54.

The spelling of 20871729477 in words is "twenty billion, eight hundred seventy-one million, seven hundred twenty-nine thousand, four hundred seventy-seven".