21077881 has 8 divisors (see below), whose sum is σ = 23112000. Its totient is φ = 19063440.

The previous prime is 21077873. The next prime is 21077887. The reversal of 21077881 is 18877012.

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

It is not a de Polignac number, because 21077881 - 2³ = 21077873 is a prime.

It is a super-2 number, since 2×21077881² = 888554134900322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21077887) 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, 2626 + ... + 7003.

It is an arithmetic number, because the mean of its divisors is an integer number (2889000).

Almost surely, 2^21077881 is an apocalyptic number.

It is an amenable number.

21077881 is a deficient number, since it is larger than the sum of its proper divisors (2034119).

21077881 is a wasteful number, since it uses less digits than its factorization.

21077881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9839.

The product of its (nonzero) digits is 6272, while the sum is 34.

The square root of 21077881 is about 4591.0653447757. The cubic root of 21077881 is about 276.2330568425.

The spelling of 21077881 in words is "twenty-one million, seventy-seven thousand, eight hundred eighty-one".