20311440 has 40 divisors (see below), whose sum is σ = 62966208. Its totient is φ = 5416320.

The previous prime is 20311439. The next prime is 20311469. The reversal of 20311440 is 4411302.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 42076 + ... + 42555.

Almost surely, 2^20311440 is an apocalyptic number.

20311440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20311440 is an abundant number, since it is smaller than the sum of its proper divisors (42654768).

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

20311440 is a wasteful number, since it uses less digits than its factorization.

20311440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84647 (or 84641 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20311440 is about 4506.8214963542. The cubic root of 20311440 is about 272.8434745229.

Adding to 20311440 its reverse (4411302), we get a palindrome (24722742).

The spelling of 20311440 in words is "twenty million, three hundred eleven thousand, four hundred forty".