31998645 has 40 divisors (see below), whose sum is σ = 65560704. Its totient is φ = 14626656.

The previous prime is 31998643. The next prime is 31998647. The reversal of 31998645 is 54689913.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31998643) and next prime (31998647).

It is not a de Polignac number, because 31998645 - 2¹ = 31998643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 31998645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31998643) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2809 + ... + 8478.

Almost surely, 2^31998645 is an apocalyptic number.

31998645 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

31998645 is an abundant number, since it is smaller than the sum of its proper divisors (33562059).

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

31998645 is a wasteful number, since it uses less digits than its factorization.

31998645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11311 (or 11302 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 31998645 is about 5656.7344820135. The cubic root of 31998645 is about 317.4757292295.

The spelling of 31998645 in words is "thirty-one million, nine hundred ninety-eight thousand, six hundred forty-five".