640710929 has 2 divisors, whose sum is σ = 640710930. Its totient is φ = 640710928.

The previous prime is 640710919. The next prime is 640710997. The reversal of 640710929 is 929017046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 478734400 + 161976529 = 21880^2 + 12727^2 .

It is a cyclic number.

It is not a de Polignac number, because 640710929 - 2⁸ = 640710673 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640710892 and 640710901.

It is not a weakly prime, because it can be changed into another prime (640710919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320355464 + 320355465.

It is an arithmetic number, because the mean of its divisors is an integer number (320355465).

Almost surely, 2^640710929 is an apocalyptic number.

It is an amenable number.

640710929 is a deficient number, since it is larger than the sum of its proper divisors (1).

640710929 is an equidigital number, since it uses as much as digits as its factorization.

640710929 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 640710929 is about 25312.2683495573. The cubic root of 640710929 is about 862.0928517038.

The spelling of 640710929 in words is "six hundred forty million, seven hundred ten thousand, nine hundred twenty-nine".