21021232020 has 96 divisors (see below), whose sum is σ = 62797908096. Its totient is φ = 5235609600.

The previous prime is 21021232009. The next prime is 21021232031. The reversal of 21021232020 is 2023212012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21021232009) and next prime (21021232031).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54960 + ... + 212280.

It is an arithmetic number, because the mean of its divisors is an integer number (654144876).

Almost surely, 2^21021232020 is an apocalyptic number.

21021232020 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 21021232020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31398954048).

21021232020 is an abundant number, since it is smaller than the sum of its proper divisors (41776676076).

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

21021232020 is a wasteful number, since it uses less digits than its factorization.

21021232020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157481 (or 157479 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21021232020 its reverse (2023212012), we get a palindrome (23044444032).

The spelling of 21021232020 in words is "twenty-one billion, twenty-one million, two hundred thirty-two thousand, twenty".