21115234420 has 24 divisors (see below), whose sum is σ = 50676562944. Its totient is φ = 7239508896.

The previous prime is 21115234351. The next prime is 21115234487. The reversal of 21115234420 is 2443251112.

It is a super-2 number, since 2×21115234420² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75411412 + ... + 75411691.

It is an arithmetic number, because the mean of its divisors is an integer number (2111523456).

Almost surely, 2^21115234420 is an apocalyptic number.

21115234420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115234420 is an abundant number, since it is smaller than the sum of its proper divisors (29561328524).

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

21115234420 is a wasteful number, since it uses less digits than its factorization.

21115234420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150823119 (or 150823117 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21115234420 its reverse (2443251112), we get a palindrome (23558485532).

The spelling of 21115234420 in words is "twenty-one billion, one hundred fifteen million, two hundred thirty-four thousand, four hundred twenty".