1645198987 has 8 divisors (see below), whose sum is σ = 1742504400. Its totient is φ = 1547952384.

The previous prime is 1645198949. The next prime is 1645199009. The reversal of 1645198987 is 7898915461.

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

It is a cyclic number.

It is not a de Polignac number, because 1645198987 - 2²³ = 1636810379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645198927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51439 + ... + 77047.

It is an arithmetic number, because the mean of its divisors is an integer number (217813050).

Almost surely, 2^1645198987 is an apocalyptic number.

1645198987 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1645198987 is a deficient number, since it is larger than the sum of its proper divisors (97305413).

1645198987 is a wasteful number, since it uses less digits than its factorization.

1645198987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29405.

The product of its digits is 4354560, while the sum is 58.

The square root of 1645198987 is about 40561.0525874268. The cubic root of 1645198987 is about 1180.5185375422.

The spelling of 1645198987 in words is "one billion, six hundred forty-five million, one hundred ninety-eight thousand, nine hundred eighty-seven".