215621449380 has 144 divisors (see below), whose sum is σ = 678655876080. Its totient is φ = 55368105984.

The previous prime is 215621449369. The next prime is 215621449457. The reversal of 215621449380 is 83944126512.

215621449380 is a `hidden beast` number, since 2 + 1 + 56 + 214 + 4 + 9 + 380 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 13515457536 + 202105991844 = 116256^2 + 449562^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 479136 + ... + 812904.

Almost surely, 2^215621449380 is an apocalyptic number.

215621449380 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 215621449380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339327938040).

215621449380 is an abundant number, since it is smaller than the sum of its proper divisors (463034426700).

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

215621449380 is a wasteful number, since it uses less digits than its factorization.

215621449380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333918 (or 333913 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The spelling of 215621449380 in words is "two hundred fifteen billion, six hundred twenty-one million, four hundred forty-nine thousand, three hundred eighty".