645719949 has 24 divisors (see below), whose sum is σ = 1090744512. Its totient is φ = 360400320.

The previous prime is 645719933. The next prime is 645719951. The reversal of 645719949 is 949917546.

It is a happy number.

645719949 is a `hidden beast` number, since 64 + 571 + 9 + 9 + 4 + 9 = 666.

It is not a de Polignac number, because 645719949 - 2⁴ = 645719933 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645719895 and 645719904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645719969) 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, 116472 + ... + 121889.

It is an arithmetic number, because the mean of its divisors is an integer number (45447688).

Almost surely, 2^645719949 is an apocalyptic number.

It is an amenable number.

645719949 is a deficient number, since it is larger than the sum of its proper divisors (445024563).

645719949 is a wasteful number, since it uses less digits than its factorization.

645719949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238417 (or 238414 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 54.

The square root of 645719949 is about 25411.0202274525. The cubic root of 645719949 is about 864.3336103984. Note that the first 3 decimals are identical.

The spelling of 645719949 in words is "six hundred forty-five million, seven hundred nineteen thousand, nine hundred forty-nine".