31378493 has 4 divisors (see below), whose sum is σ = 32460540. Its totient is φ = 30296448.

The previous prime is 31378471. The next prime is 31378507. The reversal of 31378493 is 39487313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39487313 = 61 ⋅647333.

It can be written as a sum of positive squares in 2 ways, for example, as 9597604 + 21780889 = 3098^2 + 4667^2 .

It is a cyclic number.

It is not a de Polignac number, because 31378493 - 2¹⁰ = 31377469 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31378423) 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, 540980 + ... + 541037.

It is an arithmetic number, because the mean of its divisors is an integer number (8115135).

Almost surely, 2^31378493 is an apocalyptic number.

It is an amenable number.

31378493 is a deficient number, since it is larger than the sum of its proper divisors (1082047).

31378493 is a wasteful number, since it uses less digits than its factorization.

31378493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082046.

The product of its digits is 54432, while the sum is 38.

The square root of 31378493 is about 5601.6509173636. The cubic root of 31378493 is about 315.4113815521.

The spelling of 31378493 in words is "thirty-one million, three hundred seventy-eight thousand, four hundred ninety-three".