20521605121 has 8 divisors (see below), whose sum is σ = 20664088704. Its totient is φ = 20379355200.

The previous prime is 20521605113. The next prime is 20521605127. The reversal of 20521605121 is 12150612502.

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 20521605121 - 2³ = 20521605113 is a prime.

It is a super-2 number, since 2×20521605121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20521605127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119721 + ... + 235321.

It is an arithmetic number, because the mean of its divisors is an integer number (2583011088).

Almost surely, 2^20521605121 is an apocalyptic number.

It is an amenable number.

20521605121 is a deficient number, since it is larger than the sum of its proper divisors (142483583).

20521605121 is a wasteful number, since it uses less digits than its factorization.

20521605121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116831.

The product of its (nonzero) digits is 1200, while the sum is 25.

The spelling of 20521605121 in words is "twenty billion, five hundred twenty-one million, six hundred five thousand, one hundred twenty-one".