1916660521 has 4 divisors (see below), whose sum is σ = 1918135044. Its totient is φ = 1915186000.

The previous prime is 1916660509. The next prime is 1916660527. The reversal of 1916660521 is 1250666191.

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 623251225 + 1293409296 = 24965^2 + 35964^2 .

It is a cyclic number.

It is not a de Polignac number, because 1916660521 - 2¹³ = 1916652329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1916660527) 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, 735310 + ... + 737911.

It is an arithmetic number, because the mean of its divisors is an integer number (479533761).

Almost surely, 2^1916660521 is an apocalyptic number.

It is an amenable number.

1916660521 is a deficient number, since it is larger than the sum of its proper divisors (1474523).

1916660521 is a wasteful number, since it uses less digits than its factorization.

1916660521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1474522.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 1916660521 is about 43779.6816000299. The cubic root of 1916660521 is about 1242.1719913028.

The spelling of 1916660521 in words is "one billion, nine hundred sixteen million, six hundred sixty thousand, five hundred twenty-one".