87424021 has 2 divisors, whose sum is σ = 87424022. Its totient is φ = 87424020.

The previous prime is 87424019. The next prime is 87424027. The reversal of 87424021 is 12042478.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87422500 + 1521 = 9350^2 + 39^2 .

It is a cyclic number.

It is not a de Polignac number, because 87424021 - 2¹ = 87424019 is a prime.

Together with 87424019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87424027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43712010 + 43712011.

It is an arithmetic number, because the mean of its divisors is an integer number (43712011).

Almost surely, 2^87424021 is an apocalyptic number.

It is an amenable number.

87424021 is a deficient number, since it is larger than the sum of its proper divisors (1).

87424021 is an equidigital number, since it uses as much as digits as its factorization.

87424021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 87424021 is about 9350.0813365446. The cubic root of 87424021 is about 443.8234645017.

Adding to 87424021 its reverse (12042478), we get a palindrome (99466499).

The spelling of 87424021 in words is "eighty-seven million, four hundred twenty-four thousand, twenty-one".