1618720394 has 8 divisors (see below), whose sum is σ = 2431800900. Its totient is φ = 808120096.

The previous prime is 1618720393. The next prime is 1618720421. The reversal of 1618720394 is 4930278161.

It can be written as a sum of positive squares in 2 ways, for example, as 1329550369 + 289170025 = 36463^2 + 17005^2 .

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

It is not an unprimeable number, because it can be changed into a prime (1618720393) 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, 618419 + ... + 621030.

Almost surely, 2^1618720394 is an apocalyptic number.

1618720394 is a deficient number, since it is larger than the sum of its proper divisors (813080506).

1618720394 is a wasteful number, since it uses less digits than its factorization.

1618720394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1240104.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 1618720394 is about 40233.3244214296. The cubic root of 1618720394 is about 1174.1509832354.

The spelling of 1618720394 in words is "one billion, six hundred eighteen million, seven hundred twenty thousand, three hundred ninety-four".