3717821 has 2 divisors, whose sum is σ = 3717822. Its totient is φ = 3717820.

The previous prime is 3717811. The next prime is 3717853. The reversal of 3717821 is 1287173.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2592100 + 1125721 = 1610^2 + 1061^2 .

It is an emirp because it is prime and its reverse (1287173) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3717821 - 2¹⁴ = 3701437 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3717811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1858910 + 1858911.

It is an arithmetic number, because the mean of its divisors is an integer number (1858911).

Almost surely, 2^3717821 is an apocalyptic number.

It is an amenable number.

3717821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3717821 is an equidigital number, since it uses as much as digits as its factorization.

3717821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 29.

The square root of 3717821 is about 1928.1651900187. The cubic root of 3717821 is about 154.9159586031.

It can be divided in two parts, 371 and 7821, that added together give a 13-th power (8192 = 2¹³).

The spelling of 3717821 in words is "three million, seven hundred seventeen thousand, eight hundred twenty-one".