645456642 has 32 divisors (see below), whose sum is σ = 1335398400. Its totient is φ = 207767760.

The previous prime is 645456589. The next prime is 645456649. The reversal of 645456642 is 246654546.

It is a super-2 number, since 2×645456642² = 833228553403832328, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645456594 and 645456603.

It is not an unprimeable number, because it can be changed into a prime (645456649) 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 15 ways as a sum of consecutive naturals, for example, 90109 + ... + 97007.

It is an arithmetic number, because the mean of its divisors is an integer number (41731200).

Almost surely, 2^645456642 is an apocalyptic number.

645456642 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

645456642 is an abundant number, since it is smaller than the sum of its proper divisors (689941758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645456642 is a wasteful number, since it uses less digits than its factorization.

645456642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7438.

The product of its digits is 691200, while the sum is 42.

The square root of 645456642 is about 25405.8387383688. The cubic root of 645456642 is about 864.2161105278.

The spelling of 645456642 in words is "six hundred forty-five million, four hundred fifty-six thousand, six hundred forty-two".