1621270225 has 9 divisors (see below), whose sum is σ = 2010624753. Its totient is φ = 1296855120.

The previous prime is 1621270223. The next prime is 1621270241. The reversal of 1621270225 is 5220721261.

The square root of 1621270225 is 40265.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 35319249 + 1585950976 = 5943^2 + 39824^2 .

It is not a de Polignac number, because 1621270225 - 2¹ = 1621270223 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1621270193 and 1621270202.

It is not an unprimeable number, because it can be changed into a prime (1621270223) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 197299 + ... + 205351.

Almost surely, 2^1621270225 is an apocalyptic number.

1621270225 is the 40265-th square number.

1621270225 is the 20133-rd centered octagonal number.

It is an amenable number.

1621270225 is a deficient number, since it is larger than the sum of its proper divisors (389354528).

1621270225 is an frugal number, since it uses more digits than its factorization.

1621270225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16116 (or 8058 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The cubic root of 1621270225 is about 1174.7671728209.

Adding to 1621270225 its reverse (5220721261), we get a palindrome (6841991486).

The spelling of 1621270225 in words is "one billion, six hundred twenty-one million, two hundred seventy thousand, two hundred twenty-five".