215145521 has 2 divisors, whose sum is σ = 215145522. Its totient is φ = 215145520.

The previous prime is 215145503. The next prime is 215145529. The reversal of 215145521 is 125541512.

215145521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 141871921 + 73273600 = 11911^2 + 8560^2 .

It is a cyclic number.

It is not a de Polignac number, because 215145521 - 2⁶ = 215145457 is a prime.

It is a super-2 number, since 2×215145521² = 92575190412722882, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215145529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107572760 + 107572761.

It is an arithmetic number, because the mean of its divisors is an integer number (107572761).

Almost surely, 2^215145521 is an apocalyptic number.

It is an amenable number.

215145521 is a deficient number, since it is larger than the sum of its proper divisors (1).

215145521 is an equidigital number, since it uses as much as digits as its factorization.

215145521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2000, while the sum is 26.

The square root of 215145521 is about 14667.8396841525. The cubic root of 215145521 is about 599.2077701543.

The spelling of 215145521 in words is "two hundred fifteen million, one hundred forty-five thousand, five hundred twenty-one".