31478138 has 4 divisors (see below), whose sum is σ = 47217210. Its totient is φ = 15739068.

The previous prime is 31478129. The next prime is 31478147. The reversal of 31478138 is 83187413.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (31478129) and next prime (31478147).

It can be written as a sum of positive squares in only one way, i.e., 30217009 + 1261129 = 5497^2 + 1123^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31478098 and 31478107.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7869533 + ... + 7869536.

Almost surely, 2^31478138 is an apocalyptic number.

31478138 is a deficient number, since it is larger than the sum of its proper divisors (15739072).

31478138 is a wasteful number, since it uses less digits than its factorization.

31478138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15739071.

The product of its digits is 16128, while the sum is 35.

The square root of 31478138 is about 5610.5381203589. The cubic root of 31478138 is about 315.7449004057.

The spelling of 31478138 in words is "thirty-one million, four hundred seventy-eight thousand, one hundred thirty-eight".