1645199523 has 48 divisors (see below), whose sum is σ = 2635790976. Its totient is φ = 980536320.

The previous prime is 1645199519. The next prime is 1645199573. The reversal of 1645199523 is 3259915461.

It is not a de Polignac number, because 1645199523 - 2² = 1645199519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1645199503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2851011 + ... + 2851587.

It is an arithmetic number, because the mean of its divisors is an integer number (54912312).

Almost surely, 2^1645199523 is an apocalyptic number.

1645199523 is a deficient number, since it is larger than the sum of its proper divisors (990591453).

1645199523 is a wasteful number, since it uses less digits than its factorization.

1645199523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024 (or 1021 counting only the distinct ones).

The product of its digits is 291600, while the sum is 45.

The square root of 1645199523 is about 40561.0591947498. The cubic root of 1645199523 is about 1180.5186657451.

The spelling of 1645199523 in words is "one billion, six hundred forty-five million, one hundred ninety-nine thousand, five hundred twenty-three".