42640978785997 has 2 divisors, whose sum is σ = 42640978785998. Its totient is φ = 42640978785996.

The previous prime is 42640978785967. The next prime is 42640978786057. The reversal of 42640978785997 is 79958787904624.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42433485781801 + 207493004196 = 6514099^2 + 455514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42640978785997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42640978785967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21320489392998 + 21320489392999.

It is an arithmetic number, because the mean of its divisors is an integer number (21320489392999).

Almost surely, 2^{42640978785997} is an apocalyptic number.

It is an amenable number.

42640978785997 is a deficient number, since it is larger than the sum of its proper divisors (1).

42640978785997 is an equidigital number, since it uses as much as digits as its factorization.

42640978785997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15362887680, while the sum is 85.

The spelling of 42640978785997 in words is "forty-two trillion, six hundred forty billion, nine hundred seventy-eight million, seven hundred eighty-five thousand, nine hundred ninety-seven".