42877721 has 2 divisors, whose sum is σ = 42877722. Its totient is φ = 42877720.

The previous prime is 42877691. The next prime is 42877729. The reversal of 42877721 is 12777824.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34351321 + 8526400 = 5861^2 + 2920^2 .

It is a cyclic number.

It is not a de Polignac number, because 42877721 - 2¹⁴ = 42861337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (42877729) 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, 21438860 + 21438861.

It is an arithmetic number, because the mean of its divisors is an integer number (21438861).

Almost surely, 2^42877721 is an apocalyptic number.

It is an amenable number.

42877721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42877721 is an equidigital number, since it uses as much as digits as its factorization.

42877721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43904, while the sum is 38.

The square root of 42877721 is about 6548.1082000834. The cubic root of 42877721 is about 350.0074039250.

The spelling of 42877721 in words is "forty-two million, eight hundred seventy-seven thousand, seven hundred twenty-one".