47720809 has 2 divisors, whose sum is σ = 47720810. Its totient is φ = 47720808.

The previous prime is 47720807. The next prime is 47720851. The reversal of 47720809 is 90802774.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46280809 + 1440000 = 6803^2 + 1200^2 .

It is a cyclic number.

It is not a de Polignac number, because 47720809 - 2¹ = 47720807 is a prime.

It is a super-2 number, since 2×47720809² = 4554551223228962, which contains 22 as substring.

Together with 47720807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (47720807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 23860404 + 23860405.

It is an arithmetic number, because the mean of its divisors is an integer number (23860405).

Almost surely, 2^47720809 is an apocalyptic number.

It is an amenable number.

47720809 is a deficient number, since it is larger than the sum of its proper divisors (1).

47720809 is an equidigital number, since it uses as much as digits as its factorization.

47720809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 47720809 is about 6908.0249710029. The cubic root of 47720809 is about 362.7181317347.

The spelling of 47720809 in words is "forty-seven million, seven hundred twenty thousand, eight hundred nine".