20451340 has 96 divisors (see below), whose sum is σ = 56052864. Its totient is φ = 6082560.

The previous prime is 20451329. The next prime is 20451373. The reversal of 20451340 is 4315402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30610 + ... + 31270.

It is an arithmetic number, because the mean of its divisors is an integer number (583884).

Almost surely, 2^20451340 is an apocalyptic number.

20451340 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 20451340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28026432).

20451340 is an abundant number, since it is smaller than the sum of its proper divisors (35601524).

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

20451340 is a wasteful number, since it uses less digits than its factorization.

20451340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707 (or 705 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20451340 is about 4522.3157784480. The cubic root of 20451340 is about 273.4684671214.

Adding to 20451340 its reverse (4315402), we get a palindrome (24766742).

The spelling of 20451340 in words is "twenty million, four hundred fifty-one thousand, three hundred forty".