37491981 has 4 divisors (see below), whose sum is σ = 49989312. Its totient is φ = 24994652.

The previous prime is 37491913. The next prime is 37491991. The reversal of 37491981 is 18919473.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 37491981 - 2⁹ = 37491469 is a prime.

It is a super-2 number, since 2×37491981² = 2811297278608722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (37491901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6248661 + ... + 6248666.

It is an arithmetic number, because the mean of its divisors is an integer number (12497328).

Almost surely, 2^37491981 is an apocalyptic number.

It is an amenable number.

37491981 is a deficient number, since it is larger than the sum of its proper divisors (12497331).

37491981 is a wasteful number, since it uses less digits than its factorization.

37491981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12497330.

The product of its digits is 54432, while the sum is 42.

The square root of 37491981 is about 6123.0695733431. The cubic root of 37491981 is about 334.6926147499.

The spelling of 37491981 in words is "thirty-seven million, four hundred ninety-one thousand, nine hundred eighty-one".