387721 has 2 divisors, whose sum is σ = 387722.
Its totient is φ = 387720.
The previous prime is 387707. The next prime is 387727. The reversal of 387721 is 127783.
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., 373321 + 14400 = 611^2 + 120^2
It is a cyclic number.
It is not a de Polignac number, because 387721 - 215 = 354953 is a prime.
It is a self number, because there is not a number n which added to its sum of digits gives 387721.
It is not a weakly prime, because it can be changed into another prime (387727) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 193860 + 193861.
It is an arithmetic number, because the mean of its divisors is an integer number (193861).
2387721 is an apocalyptic number.
387721 is the 360-th hex number.
It is an amenable number.
387721 is a deficient number, since it is larger than the sum of its proper divisors (1).
387721 is an equidigital number, since it uses as much as digits as its factorization.
387721 is an evil number, because the sum of its binary digits is even.
The product of its digits is 2352, while the sum is 28.
The square root of 387721 is about 622.6724660686.
The cubic root of 387721 is about 72.9188439441.
The spelling of 387721 in words is "three hundred eighty-seven thousand, seven hundred twenty-one".