21318219252 has 240 divisors, whose sum is σ = 63208696320. Its totient is φ = 6206803200.

The previous prime is 21318219233. The next prime is 21318219271. The reversal of 21318219252 is 25291281312.

21318219252 is a `hidden beast` number, since 213 + 182 + 19 + 252 = 666.

It is an interprime number because it is at equal distance from previous prime (21318219233) and next prime (21318219271).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 17345374 + ... + 17346602.

It is an arithmetic number, because the mean of its divisors is an integer number (263369568).

Almost surely, 2^21318219252 is an apocalyptic number.

21318219252 is a gapful number since it is divisible by the number (22) 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 21318219252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31604348160).

21318219252 is an abundant number, since it is smaller than the sum of its proper divisors (41890477068).

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

21318219252 is a wasteful number, since it uses less digits than its factorization.

21318219252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1444 (or 1433 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The spelling of 21318219252 in words is "twenty-one billion, three hundred eighteen million, two hundred nineteen thousand, two hundred fifty-two".