21277969968025 has 9 divisors (see below), whose sum is σ = 26384711359773. Its totient is φ = 17022357523200.

The previous prime is 21277969967957. The next prime is 21277969968067. The reversal of 21277969968025 is 52086996977212.

The square root of 21277969968025 is 4612805.

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 6369753202569 + 14908216765456 = 2523837^2 + 3861116^2 .

It is not a de Polignac number, because 21277969968025 - 2¹¹ = 21277969965977 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, 22602745 + ... + 23525305.

Almost surely, 2^{21277969968025} is an apocalyptic number.

21277969968025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21277969968025 is the 4612805-th square number.

21277969968025 is the 2306403-rd centered octagonal number.

It is an amenable number.

21277969968025 is a deficient number, since it is larger than the sum of its proper divisors (5106741391748).

21277969968025 is an frugal number, since it uses more digits than its factorization.

21277969968025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1845132 (or 922566 counting only the distinct ones).

The product of its (nonzero) digits is 411505920, while the sum is 73.

It can be divided in two parts, 2127796 and 9968025, that added together give a triangular number (12095821 = T₄₉₁₈).

The spelling of 21277969968025 in words is "twenty-one trillion, two hundred seventy-seven billion, nine hundred sixty-nine million, nine hundred sixty-eight thousand, twenty-five".