215221740 has 48 divisors (see below), whose sum is σ = 634341120. Its totient is φ = 54371520.

The previous prime is 215221729. The next prime is 215221763. The reversal of 215221740 is 47122512.

It is a self number, because there is not a number n which added to its sum of digits gives 215221740.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93256 + ... + 95535.

It is an arithmetic number, because the mean of its divisors is an integer number (13215440).

Almost surely, 2^215221740 is an apocalyptic number.

215221740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

215221740 is an abundant number, since it is smaller than the sum of its proper divisors (419119380).

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

215221740 is a wasteful number, since it uses less digits than its factorization.

215221740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188822 (or 188820 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 215221740 is about 14670.4376212845. The cubic root of 215221740 is about 599.2785216850.

The spelling of 215221740 in words is "two hundred fifteen million, two hundred twenty-one thousand, seven hundred forty".