21417081 has 8 divisors (see below), whose sum is σ = 32635584. Its totient is φ = 12238320.

The previous prime is 21417031. The next prime is 21417089. The reversal of 21417081 is 18071412.

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

It is not a de Polignac number, because 21417081 - 2⁷ = 21416953 is a prime.

It is a super-2 number, since 2×21417081² = 917382717121122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21417089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 509910 + ... + 509951.

It is an arithmetic number, because the mean of its divisors is an integer number (4079448).

Almost surely, 2^21417081 is an apocalyptic number.

21417081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21417081 is a deficient number, since it is larger than the sum of its proper divisors (11218503).

21417081 is a wasteful number, since it uses less digits than its factorization.

21417081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019871.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 21417081 is about 4627.8592243066. The cubic root of 21417081 is about 277.7069570506.

Adding to 21417081 its reverse (18071412), we get a palindrome (39488493).

The spelling of 21417081 in words is "twenty-one million, four hundred seventeen thousand, eighty-one".