216561762 has 20 divisors (see below), whose sum is σ = 485259126. Its totient is φ = 72187200.

The previous prime is 216561743. The next prime is 216561769. The reversal of 216561762 is 267165612.

It is a happy number.

216561762 is a `hidden beast` number, since 21 + 6 + 561 + 76 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 212314041 + 4247721 = 14571^2 + 2061^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (216561769) by changing a digit.

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 9 ways as a sum of consecutive naturals, for example, 668239 + ... + 668562.

Almost surely, 2^216561762 is an apocalyptic number.

216561762 is an abundant number, since it is smaller than the sum of its proper divisors (268697364).

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

216561762 is a wasteful number, since it uses less digits than its factorization.

216561762 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336815 (or 1336806 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 216561762 is about 14716.0375780983. The cubic root of 216561762 is about 600.5196997237.

The spelling of 216561762 in words is "two hundred sixteen million, five hundred sixty-one thousand, seven hundred sixty-two".