21797017918 has 16 divisors (see below), whose sum is σ = 35223659856. Its totient is φ = 10056421440.

The previous prime is 21797017897. The next prime is 21797017967. The reversal of 21797017918 is 81971079712.

It is a super-2 number, since 2×21797017918² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83968 + ... + 225043.

It is an arithmetic number, because the mean of its divisors is an integer number (2201478741).

Almost surely, 2^21797017918 is an apocalyptic number.

21797017918 is a deficient number, since it is larger than the sum of its proper divisors (13426641938).

21797017918 is a wasteful number, since it uses less digits than its factorization.

21797017918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311739.

The product of its (nonzero) digits is 444528, while the sum is 52.

The spelling of 21797017918 in words is "twenty-one billion, seven hundred ninety-seven million, seventeen thousand, nine hundred eighteen".