645279019 has 16 divisors (see below), whose sum is σ = 811895040. Its totient is φ = 498195360.

The previous prime is 645278987. The next prime is 645279023. The reversal of 645279019 is 910972546.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 645279019 - 2⁵ = 645278987 is a prime.

It is a super-2 number, since 2×645279019² = 832770024723204722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645279049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30049 + ... + 46834.

It is an arithmetic number, because the mean of its divisors is an integer number (50743440).

Almost surely, 2^645279019 is an apocalyptic number.

645279019 is a deficient number, since it is larger than the sum of its proper divisors (166616021).

645279019 is a wasteful number, since it uses less digits than its factorization.

645279019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77010.

The product of its (nonzero) digits is 136080, while the sum is 43.

The square root of 645279019 is about 25402.3427856566. The cubic root of 645279019 is about 864.1368288063.

The spelling of 645279019 in words is "six hundred forty-five million, two hundred seventy-nine thousand, nineteen".