20155121025 has 24 divisors (see below), whose sum is σ = 35886453120. Its totient is φ = 9922520640.

The previous prime is 20155121009. The next prime is 20155121033. The reversal of 20155121025 is 52012155102.

It is not a de Polignac number, because 20155121025 - 2⁴ = 20155121009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20155120986 and 20155121004.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10334985 + ... + 10336934.

It is an arithmetic number, because the mean of its divisors is an integer number (1495268880).

Almost surely, 2^20155121025 is an apocalyptic number.

20155121025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20155121025 is a deficient number, since it is larger than the sum of its proper divisors (15731332095).

20155121025 is a wasteful number, since it uses less digits than its factorization.

20155121025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20671945 (or 20671940 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 24.

Adding to 20155121025 its reverse (52012155102), we get a palindrome (72167276127).

The spelling of 20155121025 in words is "twenty billion, one hundred fifty-five million, one hundred twenty-one thousand, twenty-five".