21387155310 has 96 divisors (see below), whose sum is σ = 56401712640. Its totient is φ = 5622001344.

The previous prime is 21387155297. The next prime is 21387155311. The reversal of 21387155310 is 1355178312.

It is a happy number.

21387155310 is a `hidden beast` number, since 2 + 1 + 38 + 71 + 553 + 1 + 0 = 666.

It is a super-2 number, since 2×21387155310² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21387155311) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3634951 + ... + 3640829.

It is an arithmetic number, because the mean of its divisors is an integer number (587517840).

Almost surely, 2^21387155310 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21387155310, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28200856320).

21387155310 is an abundant number, since it is smaller than the sum of its proper divisors (35014557330).

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

21387155310 is a wasteful number, since it uses less digits than its factorization.

21387155310 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6462 (or 6459 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 21387155310 in words is "twenty-one billion, three hundred eighty-seven million, one hundred fifty-five thousand, three hundred ten".