21968109610225 has 81 divisors (see below), whose sum is σ = 29092189921803. Its totient is φ = 16453447440480.

The previous prime is 21968109610171. The next prime is 21968109610261. The reversal of 21968109610225 is 52201690186912.

It is a happy number.

The square root of 21968109610225 is 4687015.

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., 7908519459681 + 14059590150544 = 2812209^2 + 3749612^2 .

It is not a de Polignac number, because 21968109610225 - 2¹¹ = 21968109608177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 45862441536 + ... + 45862442014.

Almost surely, 2^{21968109610225} is an apocalyptic number.

21968109610225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21968109610225 is the 4687015-th square number.

21968109610225 is the 2343508-th centered octagonal number.

It is an amenable number.

21968109610225 is a deficient number, since it is larger than the sum of its proper divisors (7124080311578).

21968109610225 is an frugal number, since it uses more digits than its factorization.

21968109610225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212 (or 606 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 52.

The spelling of 21968109610225 in words is "twenty-one trillion, nine hundred sixty-eight billion, one hundred nine million, six hundred ten thousand, two hundred twenty-five".