642977 has 2 divisors, whose sum is σ = 642978. Its totient is φ = 642976.

The previous prime is 642973. The next prime is 642997. The reversal of 642977 is 779246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 512656 + 130321 = 716^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 642977 - 2² = 642973 is a prime.

It is a d-powerful number, because it can be written as 6 + 4⁴ + 9³ + 2¹⁹ + 7² + 7⁶ .

It is a plaindrome in base 9.

It is not a weakly prime, because it can be changed into another prime (642973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321488 + 321489.

It is an arithmetic number, because the mean of its divisors is an integer number (321489).

2⁶⁴²⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

642977 is a deficient number, since it is larger than the sum of its proper divisors (1).

642977 is an equidigital number, since it uses as much as digits as its factorization.

642977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 35.

The square root of 642977 is about 801.8584663143. The cubic root of 642977 is about 86.3108007895.

The spelling of 642977 in words is "six hundred forty-two thousand, nine hundred seventy-seven".