21311062420 has 72 divisors (see below), whose sum is σ = 46965118536. Its totient is φ = 8116943616.

The previous prime is 21311062403. The next prime is 21311062441. The reversal of 21311062420 is 2426011312.

It can be written as a sum of positive squares in 4 ways, for example, as 7593031044 + 13718031376 = 87138^2 + 117124^2 .

It is a super-2 number, since 2×21311062420² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21311062391 and 21311062400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1628142 + ... + 1641178.

It is an arithmetic number, because the mean of its divisors is an integer number (652293313).

Almost surely, 2^21311062420 is an apocalyptic number.

21311062420 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 21311062420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23482559268).

21311062420 is an abundant number, since it is smaller than the sum of its proper divisors (25654056116).

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

21311062420 is a wasteful number, since it uses less digits than its factorization.

21311062420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13177 (or 13128 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 21311062420 its reverse (2426011312), we get a palindrome (23737073732).

The spelling of 21311062420 in words is "twenty-one billion, three hundred eleven million, sixty-two thousand, four hundred twenty".