5211251721 has 45 divisors (see below), whose sum is σ = 8443280901. Its totient is φ = 3201726528.

The previous prime is 5211251719. The next prime is 5211251761. The reversal of 5211251721 is 1271521125.

The square root of 5211251721 is 72189.

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

5211251721 is a `hidden beast` number, since 521 + 125 + 17 + 2 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3713561721 + 1497690000 = 60939^2 + 38700^2 .

It is not a de Polignac number, because 5211251721 - 2¹ = 5211251719 is a prime.

It is a super-3 number, since 3×5211251721³ (a number of 30 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (5211251701) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 8445805 + ... + 8446421.

Almost surely, 2^5211251721 is an apocalyptic number.

5211251721 is the 72189-th square number.

5211251721 is the 36095-th centered octagonal number.

It is an amenable number.

5211251721 is a deficient number, since it is larger than the sum of its proper divisors (3232029180).

5211251721 is an frugal number, since it uses more digits than its factorization.

5211251721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1272 (or 633 counting only the distinct ones).

The product of its digits is 1400, while the sum is 27.

The cubic root of 5211251721 is about 1733.7268849433.

Adding to 5211251721 its reverse (1271521125), we get a palindrome (6482772846).

The spelling of 5211251721 in words is "five billion, two hundred eleven million, two hundred fifty-one thousand, seven hundred twenty-one".