1618749521 has 8 divisors (see below), whose sum is σ = 1689391080. Its totient is φ = 1549096192.

The previous prime is 1618749511. The next prime is 1618749557. The reversal of 1618749521 is 1259478161.

It can be written as a sum of positive squares in 4 ways, for example, as 20349121 + 1598400400 = 4511^2 + 39980^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1618749521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1618749511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243710 + ... + 250263.

It is an arithmetic number, because the mean of its divisors is an integer number (211173885).

Almost surely, 2^1618749521 is an apocalyptic number.

It is an amenable number.

1618749521 is a deficient number, since it is larger than the sum of its proper divisors (70641559).

1618749521 is a wasteful number, since it uses less digits than its factorization.

1618749521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494115.

The product of its digits is 120960, while the sum is 44.

The square root of 1618749521 is about 40233.6863958549. The cubic root of 1618749521 is about 1174.1580256892.

The spelling of 1618749521 in words is "one billion, six hundred eighteen million, seven hundred forty-nine thousand, five hundred twenty-one".