21377168367025 has 9 divisors (see below), whose sum is σ = 26507717441121. Its totient is φ = 17101716199440.

The previous prime is 21377168367019. The next prime is 21377168367109. The reversal of 21377168367025 is 52076386177312.

The square root of 21377168367025 is 4623545.

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 1533493385649 + 19843674981376 = 1238343^2 + 4454624^2 .

It is not a de Polignac number, because 21377168367025 - 2²⁷ = 21377034149297 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, 22655371 + ... + 23580079.

Almost surely, 2^{21377168367025} is an apocalyptic number.

21377168367025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21377168367025 is the 4623545-th square number.

21377168367025 is the 2311773-rd centered octagonal number.

It is an amenable number.

21377168367025 is a deficient number, since it is larger than the sum of its proper divisors (5130549074096).

21377168367025 is an frugal number, since it uses more digits than its factorization.

21377168367025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1849428 (or 924714 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 58.

The spelling of 21377168367025 in words is "twenty-one trillion, three hundred seventy-seven billion, one hundred sixty-eight million, three hundred sixty-seven thousand, twenty-five".