37218421 has 2 divisors, whose sum is σ = 37218422. Its totient is φ = 37218420.

The previous prime is 37218409. The next prime is 37218431. The reversal of 37218421 is 12481273.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37088100 + 130321 = 6090^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 37218421 - 2⁹ = 37217909 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 37218421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (37218431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18609210 + 18609211.

It is an arithmetic number, because the mean of its divisors is an integer number (18609211).

Almost surely, 2^37218421 is an apocalyptic number.

It is an amenable number.

37218421 is a deficient number, since it is larger than the sum of its proper divisors (1).

37218421 is an equidigital number, since it uses as much as digits as its factorization.

37218421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 28.

The square root of 37218421 is about 6100.6902068536. The cubic root of 37218421 is about 333.8765993274.

Adding to 37218421 its reverse (12481273), we get a palindrome (49699694).

The spelling of 37218421 in words is "thirty-seven million, two hundred eighteen thousand, four hundred twenty-one".