215661730 has 32 divisors (see below), whose sum is σ = 401679360. Its totient is φ = 83280960.

The previous prime is 215661713. The next prime is 215661737. The reversal of 215661730 is 37166512.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 215661692 and 215661701.

It is not an unprimeable number, because it can be changed into a prime (215661737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234211 + ... + 235129.

It is an arithmetic number, because the mean of its divisors is an integer number (12552480).

Almost surely, 2^215661730 is an apocalyptic number.

215661730 is a deficient number, since it is larger than the sum of its proper divisors (186017630).

215661730 is a wasteful number, since it uses less digits than its factorization.

215661730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1714.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 215661730 is about 14685.4257684277. The cubic root of 215661730 is about 599.6866233907.

The spelling of 215661730 in words is "two hundred fifteen million, six hundred sixty-one thousand, seven hundred thirty".