20347840 has 28 divisors (see below), whose sum is σ = 48454056. Its totient is φ = 8139008.

The previous prime is 20347829. The next prime is 20347843. The reversal of 20347840 is 4874302.

It is a junction number, because it is equal to n+sod(n) for n = 20347799 and 20347808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20347843) 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 3 ways as a sum of consecutive naturals, for example, 31474 + ... + 32113.

It is an arithmetic number, because the mean of its divisors is an integer number (1730502).

Almost surely, 2^20347840 is an apocalyptic number.

20347840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20347840 is an abundant number, since it is smaller than the sum of its proper divisors (28106216).

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

20347840 is an equidigital number, since it uses as much as digits as its factorization.

20347840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63604 (or 63594 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 28.

The square root of 20347840 is about 4510.8580115096. The cubic root of 20347840 is about 273.0063642646.

The spelling of 20347840 in words is "twenty million, three hundred forty-seven thousand, eight hundred forty".