21125861400 has 192 divisors, whose sum is σ = 77260769280. Its totient is φ = 4672972800.

The previous prime is 21125861387. The next prime is 21125861413. The reversal of 21125861400 is 416852112.

It is an interprime number because it is at equal distance from previous prime (21125861387) and next prime (21125861413).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49072 + ... + 211328.

It is an arithmetic number, because the mean of its divisors is an integer number (402399840).

Almost surely, 2^21125861400 is an apocalyptic number.

21125861400 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 21125861400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38630384640).

21125861400 is an abundant number, since it is smaller than the sum of its proper divisors (56134907880).

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

21125861400 is a wasteful number, since it uses less digits than its factorization.

21125861400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162314 (or 162305 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The spelling of 21125861400 in words is "twenty-one billion, one hundred twenty-five million, eight hundred sixty-one thousand, four hundred".