645861838 has 4 divisors (see below), whose sum is σ = 968792760. Its totient is φ = 322930918.

The previous prime is 645861829. The next prime is 645861857. The reversal of 645861838 is 838168546.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 645861791 and 645861800.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 161465458 + ... + 161465461.

It is an arithmetic number, because the mean of its divisors is an integer number (242198190).

Almost surely, 2^645861838 is an apocalyptic number.

645861838 is a deficient number, since it is larger than the sum of its proper divisors (322930922).

645861838 is a wasteful number, since it uses less digits than its factorization.

645861838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322930921.

The product of its digits is 1105920, while the sum is 49.

The square root of 645861838 is about 25413.8119533454. The cubic root of 645861838 is about 864.3969146477.

The spelling of 645861838 in words is "six hundred forty-five million, eight hundred sixty-one thousand, eight hundred thirty-eight".