21120780190225 has 9 divisors (see below), whose sum is σ = 26189795929467. Its totient is φ = 16896605769240.

The previous prime is 21120780190219. The next prime is 21120780190253. The reversal of 21120780190225 is 52209108702112.

The square root of 21120780190225 is 4595735.

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

It can be written as a sum of positive squares in only one way, i.e., 7603480868481 + 13517299321744 = 2757441^2 + 3676588^2 .

It is not a de Polignac number, because 21120780190225 - 2²⁷ = 21120645972497 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 22519102 + ... + 23438248.

Almost surely, 2^{21120780190225} is an apocalyptic number.

21120780190225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21120780190225 is the 4595735-th square number.

21120780190225 is the 2297868-th centered octagonal number.

It is an amenable number.

21120780190225 is a deficient number, since it is larger than the sum of its proper divisors (5069015739242).

21120780190225 is an frugal number, since it uses more digits than its factorization.

21120780190225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1838304 (or 919152 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 40.

Adding to 21120780190225 its reverse (52209108702112), we get a palindrome (73329888892337).

The spelling of 21120780190225 in words is "twenty-one trillion, one hundred twenty billion, seven hundred eighty million, one hundred ninety thousand, two hundred twenty-five".