21123421410 has 128 divisors (see below), whose sum is σ = 62443229184. Its totient is φ = 4453390080.

The previous prime is 21123421409. The next prime is 21123421411. The reversal of 21123421410 is 1412432112.

21123421410 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (21123421409) and next prime (21123421411).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21123421411) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5269627 + ... + 5273633.

It is an arithmetic number, because the mean of its divisors is an integer number (487837728).

Almost surely, 2^21123421410 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123421410, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31221614592).

21123421410 is an abundant number, since it is smaller than the sum of its proper divisors (41319807774).

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

21123421410 is a wasteful number, since it uses less digits than its factorization.

21123421410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5968.

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21123421410 its reverse (1412432112), we get a palindrome (22535853522).

The spelling of 21123421410 in words is "twenty-one billion, one hundred twenty-three million, four hundred twenty-one thousand, four hundred ten".