37813921 has 4 divisors (see below), whose sum is σ = 38054932. Its totient is φ = 37572912.

The previous prime is 37813901. The next prime is 37813939. The reversal of 37813921 is 12931873.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12931873 = 1499 ⋅8627.

It can be written as a sum of positive squares in 2 ways, for example, as 5198400 + 32615521 = 2280^2 + 5711^2 .

It is a cyclic number.

It is not a de Polignac number, because 37813921 - 2⁹ = 37813409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (37813901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120270 + ... + 120583.

It is an arithmetic number, because the mean of its divisors is an integer number (9513733).

Almost surely, 2^37813921 is an apocalyptic number.

It is an amenable number.

37813921 is a deficient number, since it is larger than the sum of its proper divisors (241011).

37813921 is a wasteful number, since it uses less digits than its factorization.

37813921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241010.

The product of its digits is 9072, while the sum is 34.

The square root of 37813921 is about 6149.3024807697. The cubic root of 37813921 is about 335.6478766916.

The spelling of 37813921 in words is "thirty-seven million, eight hundred thirteen thousand, nine hundred twenty-one".