21097196720 has 20 divisors (see below), whose sum is σ = 49050982560. Its totient is φ = 8438878656.

The previous prime is 21097196647. The next prime is 21097196753. The reversal of 21097196720 is 2769179012.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131857400 + ... + 131857559.

It is an arithmetic number, because the mean of its divisors is an integer number (2452549128).

Almost surely, 2^21097196720 is an apocalyptic number.

21097196720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21097196720 is an abundant number, since it is smaller than the sum of its proper divisors (27953785840).

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

21097196720 is a wasteful number, since it uses less digits than its factorization.

21097196720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263714972 (or 263714966 counting only the distinct ones).

The product of its (nonzero) digits is 95256, while the sum is 44.

The spelling of 21097196720 in words is "twenty-one billion, ninety-seven million, one hundred ninety-six thousand, seven hundred twenty".