1428657521 has 4 divisors (see below), whose sum is σ = 1429937652. Its totient is φ = 1427377392.

The previous prime is 1428657511. The next prime is 1428657539. The reversal of 1428657521 is 1257568241.

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 23232400 + 1405425121 = 4820^2 + 37489^2 .

It is a cyclic number.

It is not a de Polignac number, because 1428657521 - 2⁶ = 1428657457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1428657511) 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, 638390 + ... + 640623.

It is an arithmetic number, because the mean of its divisors is an integer number (357484413).

Almost surely, 2^1428657521 is an apocalyptic number.

It is an amenable number.

1428657521 is a deficient number, since it is larger than the sum of its proper divisors (1280131).

1428657521 is a wasteful number, since it uses less digits than its factorization.

1428657521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280130.

The product of its digits is 134400, while the sum is 41.

The square root of 1428657521 is about 37797.5861795433. The cubic root of 1428657521 is about 1126.2705043194.

The spelling of 1428657521 in words is "one billion, four hundred twenty-eight million, six hundred fifty-seven thousand, five hundred twenty-one".