1645608993 has 24 divisors (see below), whose sum is σ = 2702516832. Its totient is φ = 885032064.

The previous prime is 1645608989. The next prime is 1645609001. The reversal of 1645608993 is 3998065461.

It is not a de Polignac number, because 1645608993 - 2² = 1645608989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1645608193) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 326755 + ... + 331752.

It is an arithmetic number, because the mean of its divisors is an integer number (112604868).

Almost surely, 2^1645608993 is an apocalyptic number.

It is an amenable number.

1645608993 is a deficient number, since it is larger than the sum of its proper divisors (1056907839).

1645608993 is a wasteful number, since it uses less digits than its factorization.

1645608993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658541 (or 658534 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 51.

The square root of 1645608993 is about 40566.1064560059. The cubic root of 1645608993 is about 1180.6165964973.

The spelling of 1645608993 in words is "one billion, six hundred forty-five million, six hundred eight thousand, nine hundred ninety-three".