20381340 has 48 divisors (see below), whose sum is σ = 65221632. Its totient is φ = 4658496.

The previous prime is 20381329. The next prime is 20381359. The reversal of 20381340 is 4318302.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 23844 + ... + 24683.

It is an arithmetic number, because the mean of its divisors is an integer number (1358784).

Almost surely, 2^20381340 is an apocalyptic number.

20381340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20381340 is an abundant number, since it is smaller than the sum of its proper divisors (44840292).

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

20381340 is a wasteful number, since it uses less digits than its factorization.

20381340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48546 (or 48544 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 20381340 is about 4514.5697469416. The cubic root of 20381340 is about 273.1561049533.

Adding to 20381340 its reverse (4318302), we get a palindrome (24699642).

The spelling of 20381340 in words is "twenty million, three hundred eighty-one thousand, three hundred forty".