47781809 has 2 divisors, whose sum is σ = 47781810. Its totient is φ = 47781808.

The previous prime is 47781749. The next prime is 47781817. The reversal of 47781809 is 90818774.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42941809 + 4840000 = 6553^2 + 2200^2 .

It is a cyclic number.

It is not a de Polignac number, because 47781809 - 2²⁴ = 31004593 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 47781809.

It is not a weakly prime, because it can be changed into another prime (47781829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 23890904 + 23890905.

It is an arithmetic number, because the mean of its divisors is an integer number (23890905).

Almost surely, 2^47781809 is an apocalyptic number.

It is an amenable number.

47781809 is a deficient number, since it is larger than the sum of its proper divisors (1).

47781809 is an equidigital number, since it uses as much as digits as its factorization.

47781809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 47781809 is about 6912.4387158224. The cubic root of 47781809 is about 362.8726162990.

The spelling of 47781809 in words is "forty-seven million, seven hundred eighty-one thousand, eight hundred nine".