1025221555 has 4 divisors (see below), whose sum is σ = 1230265872. Its totient is φ = 820177240.

The previous prime is 1025221531. The next prime is 1025221577. The reversal of 1025221555 is 5551225201.

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

It is a de Polignac number, because none of the positive numbers 2^k-1025221555 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, 102522151 + ... + 102522160.

It is an arithmetic number, because the mean of its divisors is an integer number (307566468).

Almost surely, 2^1025221555 is an apocalyptic number.

1025221555 is a deficient number, since it is larger than the sum of its proper divisors (205044317).

1025221555 is an equidigital number, since it uses as much as digits as its factorization.

1025221555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205044316.

The product of its (nonzero) digits is 5000, while the sum is 28.

The square root of 1025221555 is about 32019.0811079893. The cubic root of 1025221555 is about 1008.3374782669.

Adding to 1025221555 its reverse (5551225201), we get a palindrome (6576446756).

The spelling of 1025221555 in words is "one billion, twenty-five million, two hundred twenty-one thousand, five hundred fifty-five".