30681840 has 120 divisors (see below), whose sum is σ = 110684880. Its totient is φ = 7010304.

The previous prime is 30681823. The next prime is 30681857. The reversal of 30681840 is 4818603.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (30681823) and next prime (30681857).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 30681798 and 30681807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10456 + ... + 13064.

It is an arithmetic number, because the mean of its divisors is an integer number (922374).

Almost surely, 2^30681840 is an apocalyptic number.

30681840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 30681840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55342440).

30681840 is an abundant number, since it is smaller than the sum of its proper divisors (80003040).

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

30681840 is a wasteful number, since it uses less digits than its factorization.

30681840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2639 (or 2626 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 30681840 is about 5539.1190635335. The cubic root of 30681840 is about 313.0596775702.

The spelling of 30681840 in words is "thirty million, six hundred eighty-one thousand, eight hundred forty".