20311221440 has 28 divisors (see below), whose sum is σ = 48366096816. Its totient is φ = 8124488448.

The previous prime is 20311221439. The next prime is 20311221457. The reversal of 20311221440 is 4412211302.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31735964 + ... + 31736603.

Almost surely, 2^20311221440 is an apocalyptic number.

20311221440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20311221440 is an abundant number, since it is smaller than the sum of its proper divisors (28054875376).

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

20311221440 is an equidigital number, since it uses as much as digits as its factorization.

20311221440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63472584 (or 63472574 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 20311221440 its reverse (4412211302), we get a palindrome (24723432742).

The spelling of 20311221440 in words is "twenty billion, three hundred eleven million, two hundred twenty-one thousand, four hundred forty".