642280665 has 64 divisors (see below), whose sum is σ = 1131863040. Its totient is φ = 309104640.

The previous prime is 642280663. The next prime is 642280679. The reversal of 642280665 is 566082246.

It is not a de Polignac number, because 642280665 - 2¹ = 642280663 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (642280663) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2664945 + ... + 2665185.

It is an arithmetic number, because the mean of its divisors is an integer number (17685360).

Almost surely, 2^642280665 is an apocalyptic number.

642280665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

642280665 is a deficient number, since it is larger than the sum of its proper divisors (489582375).

642280665 is a wasteful number, since it uses less digits than its factorization.

642280665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514.

The product of its (nonzero) digits is 138240, while the sum is 39.

The square root of 642280665 is about 25343.2567954476. The cubic root of 642280665 is about 862.7963174262.

The spelling of 642280665 in words is "six hundred forty-two million, two hundred eighty thousand, six hundred sixty-five".