30491640 has 96 divisors (see below), whose sum is σ = 102800880. Its totient is φ = 8128512.

The previous prime is 30491609. The next prime is 30491647. The reversal of 30491640 is 4619403.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30491647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8152 + ... + 11288.

Almost surely, 2^30491640 is an apocalyptic number.

30491640 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 30491640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51400440).

30491640 is an abundant number, since it is smaller than the sum of its proper divisors (72309240).

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

30491640 is a wasteful number, since it uses less digits than its factorization.

30491640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3163 (or 3147 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 30491640 is about 5521.9235778848. The cubic root of 30491640 is about 312.4114394382.

The spelling of 30491640 in words is "thirty million, four hundred ninety-one thousand, six hundred forty".