21571620400 has 120 divisors (see below), whose sum is σ = 57098207088. Its totient is φ = 7766400000.

The previous prime is 21571620353. The next prime is 21571620407. The reversal of 21571620400 is 402617512.

It is not an unprimeable number, because it can be changed into a prime (21571620407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 420130 + ... + 468670.

Almost surely, 2^21571620400 is an apocalyptic number.

21571620400 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 21571620400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28549103544).

21571620400 is an abundant number, since it is smaller than the sum of its proper divisors (35526586688).

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

21571620400 is a wasteful number, since it uses less digits than its factorization.

21571620400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48671 (or 48660 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The spelling of 21571620400 in words is "twenty-one billion, five hundred seventy-one million, six hundred twenty thousand, four hundred".