21111021024 has 96 divisors (see below), whose sum is σ = 56431742976. Its totient is φ = 6909235200.

The previous prime is 21111021023. The next prime is 21111021031. The reversal of 21111021024 is 42012011112.

It is a tau number, because it is divible by the number of its divisors (96).

It is a junction number, because it is equal to n+sod(n) for n = 21111020994 and 21111021012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111021023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1173699 + ... + 1191549.

It is an arithmetic number, because the mean of its divisors is an integer number (587830656).

Almost surely, 2^21111021024 is an apocalyptic number.

21111021024 is a gapful number since it is divisible by the number (24) 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 21111021024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28215871488).

21111021024 is an abundant number, since it is smaller than the sum of its proper divisors (35320721952).

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

21111021024 is a wasteful number, since it uses less digits than its factorization.

21111021024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18088 (or 18080 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21111021024 its reverse (42012011112), we get a palindrome (63123032136).

The spelling of 21111021024 in words is "twenty-one billion, one hundred eleven million, twenty-one thousand, twenty-four".