645779254 has 8 divisors (see below), whose sum is σ = 978259968. Its totient is φ = 319692600.

The previous prime is 645779227. The next prime is 645779269. The reversal of 645779254 is 452977546.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 645779198 and 645779207.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1598262 + ... + 1598665.

It is an arithmetic number, because the mean of its divisors is an integer number (122282496).

Almost surely, 2^645779254 is an apocalyptic number.

645779254 is a deficient number, since it is larger than the sum of its proper divisors (332480714).

645779254 is a wasteful number, since it uses less digits than its factorization.

645779254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3197030.

The product of its digits is 2116800, while the sum is 49.

The square root of 645779254 is about 25412.1871156341. The cubic root of 645779254 is about 864.3600706493.

The spelling of 645779254 in words is "six hundred forty-five million, seven hundred seventy-nine thousand, two hundred fifty-four".