31997155 has 8 divisors (see below), whose sum is σ = 38570112. Its totient is φ = 25482048.

The previous prime is 31997153. The next prime is 31997171. The reversal of 31997155 is 55179913.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31997155 - 2¹ = 31997153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31997153) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13234 + ... + 15463.

It is an arithmetic number, because the mean of its divisors is an integer number (4821264).

Almost surely, 2^31997155 is an apocalyptic number.

31997155 is a deficient number, since it is larger than the sum of its proper divisors (6572957).

31997155 is a wasteful number, since it uses less digits than its factorization.

31997155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28925.

The product of its digits is 42525, while the sum is 40.

The square root of 31997155 is about 5656.6027790539. The cubic root of 31997155 is about 317.4708014565.

The spelling of 31997155 in words is "thirty-one million, nine hundred ninety-seven thousand, one hundred fifty-five".