20347640 has 64 divisors (see below), whose sum is σ = 50621760. Its totient is φ = 7321600.

The previous prime is 20347633. The next prime is 20347661. The reversal of 20347640 is 4674302.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14990 + ... + 16290.

It is an arithmetic number, because the mean of its divisors is an integer number (790965).

Almost surely, 2^20347640 is an apocalyptic number.

20347640 is a gapful number since it is divisible by the number (20) 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 20347640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25310880).

20347640 is an abundant number, since it is smaller than the sum of its proper divisors (30274120).

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

20347640 is a wasteful number, since it uses less digits than its factorization.

20347640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1352 (or 1348 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 26.

The square root of 20347640 is about 4510.8358427236. The cubic root of 20347640 is about 273.0054697970.

The spelling of 20347640 in words is "twenty million, three hundred forty-seven thousand, six hundred forty".