31785138 has 192 divisors, whose sum is σ = 97044480. Its totient is φ = 7257600.

The previous prime is 31785101. The next prime is 31785181. The reversal of 31785138 is 83158713.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 447643 + ... + 447713.

It is an arithmetic number, because the mean of its divisors is an integer number (505440).

Almost surely, 2^31785138 is an apocalyptic number.

31785138 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 31785138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48522240).

31785138 is an abundant number, since it is smaller than the sum of its proper divisors (65259342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31785138 is a wasteful number, since it uses less digits than its factorization.

31785138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 130 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 31785138 is about 5637.8309658946. The cubic root of 31785138 is about 316.7680470719.

The spelling of 31785138 in words is "thirty-one million, seven hundred eighty-five thousand, one hundred thirty-eight".