21078101 has 8 divisors (see below), whose sum is σ = 23092608. Its totient is φ = 19080000.

The previous prime is 21078089. The next prime is 21078103. The reversal of 21078101 is 10187012.

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 21078101 - 2¹⁴ = 21061717 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21078103) 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, 1325 + ... + 6626.

It is an arithmetic number, because the mean of its divisors is an integer number (2886576).

Almost surely, 2^21078101 is an apocalyptic number.

21078101 is the 2651-st octagonal number.

It is an amenable number.

21078101 is a deficient number, since it is larger than the sum of its proper divisors (2014507).

21078101 is a wasteful number, since it uses less digits than its factorization.

21078101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8203.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 21078101 is about 4591.0893042937. The cubic root of 21078101 is about 276.2340178984.

The spelling of 21078101 in words is "twenty-one million, seventy-eight thousand, one hundred one".