4157521 has 3 divisors (see below), whose sum is σ = 4159561. Its totient is φ = 4155482.

The previous prime is 4157513. The next prime is 4157563. The reversal of 4157521 is 1257514.

The square root of 4157521 is 2039.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1257514 = 2 ⋅628757.

It is not a de Polignac number, because 4157521 - 2³ = 4157513 is a prime.

It is a Duffinian number.

4157521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (4157501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1020 + ... + 3058.

Almost surely, 2^4157521 is an apocalyptic number.

4157521 is the 2039-th square number.

4157521 is the 1020-th centered octagonal number.

It is an amenable number.

4157521 is a deficient number, since it is larger than the sum of its proper divisors (2040).

4157521 is an frugal number, since it uses more digits than its factorization.

4157521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4078 (or 2039 counting only the distinct ones).

The product of its digits is 1400, while the sum is 25.

The cubic root of 4157521 is about 160.7970772676.

Multiplying 4157521 by its sum of digits (25), we get a square (103938025 = 10195²).

The spelling of 4157521 in words is "four million, one hundred fifty-seven thousand, five hundred twenty-one".