3700000021 has 2 divisors, whose sum is σ = 3700000022. Its totient is φ = 3700000020.

The previous prime is 3699999991. The next prime is 3700000039. The reversal of 3700000021 is 1200000073.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3574246225 + 125753796 = 59785^2 + 11214^2 .

It is an emirp because it is prime and its reverse (1200000073) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3700000021 - 2⁹ = 3699999509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3699999947 and 3700000010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3700000721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1850000010 + 1850000011.

It is an arithmetic number, because the mean of its divisors is an integer number (1850000011).

Almost surely, 2^3700000021 is an apocalyptic number.

It is an amenable number.

3700000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3700000021 is an equidigital number, since it uses as much as digits as its factorization.

3700000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42, while the sum is 13.

The square root of 3700000021 is about 60827.6254756011. The cubic root of 3700000021 is about 1546.6803766982.

Adding to 3700000021 its reverse (1200000073), we get a palindrome (4900000094).

The spelling of 3700000021 in words is "three billion, seven hundred million, twenty-one", and thus it is an aban number.