31128101 has 4 divisors (see below), whose sum is σ = 31261932. Its totient is φ = 30994272.

The previous prime is 31128091. The next prime is 31128127. The reversal of 31128101 is 10182113.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15007876 + 16120225 = 3874^2 + 4015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31128101 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31128101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31128151) 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, 66566 + ... + 67031.

It is an arithmetic number, because the mean of its divisors is an integer number (7815483).

Almost surely, 2^31128101 is an apocalyptic number.

It is an amenable number.

31128101 is a deficient number, since it is larger than the sum of its proper divisors (133831).

31128101 is a wasteful number, since it uses less digits than its factorization.

31128101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133830.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 31128101 is about 5579.2563124488. The cubic root of 31128101 is about 314.5701738142.

The spelling of 31128101 in words is "thirty-one million, one hundred twenty-eight thousand, one hundred one".