31748681 has 4 divisors (see below), whose sum is σ = 32772864. Its totient is φ = 30724500.

The previous prime is 31748669. The next prime is 31748683. The reversal of 31748681 is 18684713.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18684713 = 647 ⋅28879.

It is a cyclic number.

It is not a de Polignac number, because 31748681 - 2¹⁸ = 31486537 is a prime.

It is a super-2 number, since 2×31748681² = 2015957490479522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31748683) 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, 512045 + ... + 512106.

It is an arithmetic number, because the mean of its divisors is an integer number (8193216).

Almost surely, 2^31748681 is an apocalyptic number.

31748681 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

31748681 is a deficient number, since it is larger than the sum of its proper divisors (1024183).

31748681 is a wasteful number, since it uses less digits than its factorization.

31748681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024182.

The product of its digits is 32256, while the sum is 38.

The square root of 31748681 is about 5634.5967912531. The cubic root of 31748681 is about 316.6468915937.

The spelling of 31748681 in words is "thirty-one million, seven hundred forty-eight thousand, six hundred eighty-one".