20521530005155 has 8 divisors (see below), whose sum is σ = 25475002765200. Its totient is φ = 15851112831456.

The previous prime is 20521530005147. The next prime is 20521530005173. The reversal of 20521530005155 is 55150003512502.

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 20521530005155 - 2³ = 20521530005147 is a prime.

It is a super-2 number, since 2×20521530005155² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20521530005155.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70763896425 + ... + 70763896714.

It is an arithmetic number, because the mean of its divisors is an integer number (3184375345650).

Almost surely, 2^{20521530005155} is an apocalyptic number.

20521530005155 is a deficient number, since it is larger than the sum of its proper divisors (4953472760045).

20521530005155 is a wasteful number, since it uses less digits than its factorization.

20521530005155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141527793173.

The product of its (nonzero) digits is 37500, while the sum is 34.

Adding to 20521530005155 its reverse (55150003512502), we get a palindrome (75671533517657).

The spelling of 20521530005155 in words is "twenty trillion, five hundred twenty-one billion, five hundred thirty million, five thousand, one hundred fifty-five".