21343031550 has 192 divisors, whose sum is σ = 62047814400. Its totient is φ = 5379696000.

The previous prime is 21343031537. The next prime is 21343031551. The reversal of 21343031550 is 5513034312.

21343031550 is a `hidden beast` number, since 2 + 1 + 343 + 0 + 315 + 5 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343031551) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 17980057 + ... + 17981243.

It is an arithmetic number, because the mean of its divisors is an integer number (323165700).

Almost surely, 2^21343031550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21343031550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31023907200).

21343031550 is an abundant number, since it is smaller than the sum of its proper divisors (40704782850).

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

21343031550 is a wasteful number, since it uses less digits than its factorization.

21343031550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1928 (or 1917 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

Adding to 21343031550 its reverse (5513034312), we get a palindrome (26856065862).

The spelling of 21343031550 in words is "twenty-one billion, three hundred forty-three million, thirty-one thousand, five hundred fifty".