3897817055521 has 27 divisors (see below), whose sum is σ = 4018355595891. Its totient is φ = 3780873995184.

The previous prime is 3897817055507. The next prime is 3897817055543. The reversal of 3897817055521 is 1255507187983.

It is a happy number.

The square root of 3897817055521 is 1974289.

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., 2118698580625 + 1779118474896 = 1455575^2 + 1333836^2 .

It is not a de Polignac number, because 3897817055521 - 2⁷ = 3897817055393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3897817055521.

It is not an unprimeable number, because it can be changed into a prime (3897817055551) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10449911491 + ... + 10449911863.

It is an arithmetic number, because the mean of its divisors is an integer number (148827985033).

Almost surely, 2^{3897817055521} is an apocalyptic number.

3897817055521 is the 1974289-th square number.

3897817055521 is the 987145-th centered octagonal number.

It is an amenable number.

3897817055521 is a deficient number, since it is larger than the sum of its proper divisors (120538540370).

3897817055521 is an frugal number, since it uses more digits than its factorization.

3897817055521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038 (or 519 counting only the distinct ones).

The product of its (nonzero) digits is 21168000, while the sum is 61.

The spelling of 3897817055521 in words is "three trillion, eight hundred ninety-seven billion, eight hundred seventeen million, fifty-five thousand, five hundred twenty-one".