10521157217 has 4 divisors (see below), whose sum is σ = 11140048836. Its totient is φ = 9902265600.

The previous prime is 10521157181. The next prime is 10521157249. The reversal of 10521157217 is 71275112501.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7704626176 + 2816531041 = 87776^2 + 53071^2 .

It is a cyclic number.

It is not a de Polignac number, because 10521157217 - 2¹² = 10521153121 is a prime.

It is a super-2 number, since 2×10521157217² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10521157267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309445784 + ... + 309445817.

It is an arithmetic number, because the mean of its divisors is an integer number (2785012209).

Almost surely, 2^10521157217 is an apocalyptic number.

10521157217 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

10521157217 is a deficient number, since it is larger than the sum of its proper divisors (618891619).

10521157217 is an equidigital number, since it uses as much as digits as its factorization.

10521157217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618891618.

The product of its (nonzero) digits is 4900, while the sum is 32.

Adding to 10521157217 its reverse (71275112501), we get a palindrome (81796269718).

The spelling of 10521157217 in words is "ten billion, five hundred twenty-one million, one hundred fifty-seven thousand, two hundred seventeen".