1651428521 has 4 divisors (see below), whose sum is σ = 1661947332. Its totient is φ = 1640909712.

The previous prime is 1651428509. The next prime is 1651428587. The reversal of 1651428521 is 1258241561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1258241561 = 197 ⋅6387013.

It can be written as a sum of positive squares in 2 ways, for example, as 416608921 + 1234819600 = 20411^2 + 35140^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1651428521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1651428421) 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, 5259170 + ... + 5259483.

It is an arithmetic number, because the mean of its divisors is an integer number (415486833).

Almost surely, 2^1651428521 is an apocalyptic number.

It is an amenable number.

1651428521 is a deficient number, since it is larger than the sum of its proper divisors (10518811).

1651428521 is a wasteful number, since it uses less digits than its factorization.

1651428521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10518810.

The product of its digits is 19200, while the sum is 35.

The square root of 1651428521 is about 40637.7720969051. The cubic root of 1651428521 is about 1182.0066691390.

The spelling of 1651428521 in words is "one billion, six hundred fifty-one million, four hundred twenty-eight thousand, five hundred twenty-one".