87478409 has 2 divisors, whose sum is σ = 87478410. Its totient is φ = 87478408.

The previous prime is 87478381. The next prime is 87478411. The reversal of 87478409 is 90487478.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77492809 + 9985600 = 8803^2 + 3160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87478409 is a prime.

Together with 87478411, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87478429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43739204 + 43739205.

It is an arithmetic number, because the mean of its divisors is an integer number (43739205).

Almost surely, 2^87478409 is an apocalyptic number.

It is an amenable number.

87478409 is a deficient number, since it is larger than the sum of its proper divisors (1).

87478409 is an equidigital number, since it uses as much as digits as its factorization.

87478409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 451584, while the sum is 47.

The square root of 87478409 is about 9352.9893082372. The cubic root of 87478409 is about 443.9154821811.

The spelling of 87478409 in words is "eighty-seven million, four hundred seventy-eight thousand, four hundred nine".