216440977 has 4 divisors (see below), whose sum is σ = 223422976. Its totient is φ = 209458980.

The previous prime is 216440941. The next prime is 216440981. The reversal of 216440977 is 779044612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216440977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216447977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3490953 + ... + 3491014.

It is an arithmetic number, because the mean of its divisors is an integer number (55855744).

Almost surely, 2^216440977 is an apocalyptic number.

It is an amenable number.

216440977 is a deficient number, since it is larger than the sum of its proper divisors (6981999).

216440977 is an equidigital number, since it uses as much as digits as its factorization.

216440977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6981998.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 216440977 is about 14711.9331496578. The cubic root of 216440977 is about 600.4080344872.

The spelling of 216440977 in words is "two hundred sixteen million, four hundred forty thousand, nine hundred seventy-seven".