21081797 has 8 divisors (see below), whose sum is σ = 23034240. Its totient is φ = 19135360.

The previous prime is 21081793. The next prime is 21081833. The reversal of 21081797 is 79718012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21081797 - 2² = 21081793 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21081791) 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, 9188 + ... + 11250.

It is an arithmetic number, because the mean of its divisors is an integer number (2879280).

Almost surely, 2^21081797 is an apocalyptic number.

It is an amenable number.

21081797 is a deficient number, since it is larger than the sum of its proper divisors (1952443).

21081797 is a wasteful number, since it uses less digits than its factorization.

21081797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 21081797 is about 4591.4918055029. The cubic root of 21081797 is about 276.2501626365.

The spelling of 21081797 in words is "twenty-one million, eighty-one thousand, seven hundred ninety-seven".