645092220 has 24 divisors (see below), whose sum is σ = 1806258384. Its totient is φ = 172024576.

The previous prime is 645092213. The next prime is 645092221. The reversal of 645092220 is 22290546.

It is a super-2 number, since 2×645092220² = 832287944609056800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645092221) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 5375709 + ... + 5375828.

It is an arithmetic number, because the mean of its divisors is an integer number (75260766).

Almost surely, 2^645092220 is an apocalyptic number.

645092220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645092220 is an abundant number, since it is smaller than the sum of its proper divisors (1161166164).

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

645092220 is a wasteful number, since it uses less digits than its factorization.

645092220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10751549 (or 10751547 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 645092220 is about 25398.6657129858. The cubic root of 645092220 is about 864.0534356954.

The spelling of 645092220 in words is "six hundred forty-five million, ninety-two thousand, two hundred twenty".