20715715721511 has 24 divisors (see below), whose sum is σ = 30131768787120. Its totient is φ = 13714318555776.

The previous prime is 20715715721473. The next prime is 20715715721593. The reversal of 20715715721511 is 11512751751702.

20715715721511 is a `hidden beast` number, since 2 + 0 + 7 + 1 + 5 + 71 + 572 + 1 + 5 + 1 + 1 = 666.

It is not a de Polignac number, because 20715715721511 - 2¹⁴ = 20715715705127 is a prime.

It is a super-2 number, since 2×20715715721511² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20715715721611) 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, 13192710 + ... + 14679203.

It is an arithmetic number, because the mean of its divisors is an integer number (1255490366130).

Almost surely, 2^{20715715721511} is an apocalyptic number.

20715715721511 is a deficient number, since it is larger than the sum of its proper divisors (9416053065609).

20715715721511 is a wasteful number, since it uses less digits than its factorization.

20715715721511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27872495 (or 27872492 counting only the distinct ones).

The product of its (nonzero) digits is 171500, while the sum is 45.

The spelling of 20715715721511 in words is "twenty trillion, seven hundred fifteen billion, seven hundred fifteen million, seven hundred twenty-one thousand, five hundred eleven".