21097655518 has 16 divisors (see below), whose sum is σ = 33504653520. Its totient is φ = 9935856576.

The previous prime is 21097655507. The next prime is 21097655519. The reversal of 21097655518 is 81555679012.

It is a super-2 number, since 2×21097655518² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097655519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1598055 + ... + 1611202.

It is an arithmetic number, because the mean of its divisors is an integer number (2094040845).

Almost surely, 2^21097655518 is an apocalyptic number.

21097655518 is a deficient number, since it is larger than the sum of its proper divisors (12406998002).

21097655518 is a wasteful number, since it uses less digits than its factorization.

21097655518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3209451.

The product of its (nonzero) digits is 756000, while the sum is 49.

The spelling of 21097655518 in words is "twenty-one billion, ninety-seven million, six hundred fifty-five thousand, five hundred eighteen".