216739597981 has 16 divisors (see below), whose sum is σ = 226338292224. Its totient is φ = 207361312704.

The previous prime is 216739597973. The next prime is 216739598003. The reversal of 216739597981 is 189795937612.

It is a cyclic number.

It is not a de Polignac number, because 216739597981 - 2³ = 216739597973 is a prime.

It is a super-2 number, since 2×216739597981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216739597951) 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, 1305015 + ... + 1461691.

It is an arithmetic number, because the mean of its divisors is an integer number (14146143264).

Almost surely, 2^216739597981 is an apocalyptic number.

It is an amenable number.

216739597981 is a deficient number, since it is larger than the sum of its proper divisors (9598694243).

216739597981 is a wasteful number, since it uses less digits than its factorization.

216739597981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157380.

The product of its digits is 51438240, while the sum is 67.

The spelling of 216739597981 in words is "two hundred sixteen billion, seven hundred thirty-nine million, five hundred ninety-seven thousand, nine hundred eighty-one".