21142120420 has 96 divisors (see below), whose sum is σ = 48193326720. Its totient is φ = 7763558400.

The previous prime is 21142120411. The next prime is 21142120429. The reversal of 21142120420 is 2402124112.

It is an interprime number because it is at equal distance from previous prime (21142120411) and next prime (21142120429).

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21142120429) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3610495 + ... + 3616345.

It is an arithmetic number, because the mean of its divisors is an integer number (502013820).

Almost surely, 2^21142120420 is an apocalyptic number.

21142120420 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 21142120420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24096663360).

21142120420 is an abundant number, since it is smaller than the sum of its proper divisors (27051206300).

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

21142120420 is a wasteful number, since it uses less digits than its factorization.

21142120420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6173 (or 6171 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21142120420 its reverse (2402124112), we get a palindrome (23544244532).

The spelling of 21142120420 in words is "twenty-one billion, one hundred forty-two million, one hundred twenty thousand, four hundred twenty".