20425221101555 has 4 divisors (see below), whose sum is σ = 24510265321872. Its totient is φ = 16340176881240.

The previous prime is 20425221101543. The next prime is 20425221101611. The reversal of 20425221101555 is 55510112252402.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20425221101555 - 2¹² = 20425221097459 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2042522110151 + ... + 2042522110160.

It is an arithmetic number, because the mean of its divisors is an integer number (6127566330468).

Almost surely, 2^{20425221101555} is an apocalyptic number.

20425221101555 is a deficient number, since it is larger than the sum of its proper divisors (4085044220317).

20425221101555 is an equidigital number, since it uses as much as digits as its factorization.

20425221101555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4085044220316.

The product of its (nonzero) digits is 40000, while the sum is 35.

Adding to 20425221101555 its reverse (55510112252402), we get a palindrome (75935333353957).

The spelling of 20425221101555 in words is "twenty trillion, four hundred twenty-five billion, two hundred twenty-one million, one hundred one thousand, five hundred fifty-five".