21071417 has 4 divisors (see below), whose sum is σ = 21585396. Its totient is φ = 20557440.

The previous prime is 21071387. The next prime is 21071423. The reversal of 21071417 is 71417012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6295081 + 14776336 = 2509^2 + 3844^2 .

It is a cyclic number.

It is not a de Polignac number, because 21071417 - 2¹⁰ = 21070393 is a prime.

It is a super-2 number, since 2×21071417² = 888009228775778, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21071392 and 21071401.

It is not an unprimeable number, because it can be changed into a prime (21071447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256928 + ... + 257009.

It is an arithmetic number, because the mean of its divisors is an integer number (5396349).

Almost surely, 2^21071417 is an apocalyptic number.

It is an amenable number.

21071417 is a deficient number, since it is larger than the sum of its proper divisors (513979).

21071417 is an equidigital number, since it uses as much as digits as its factorization.

21071417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513978.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 21071417 is about 4590.3613147551. The cubic root of 21071417 is about 276.2048162897.

Adding to 21071417 its reverse (71417012), we get a palindrome (92488429).

Subtracting 21071417 from its reverse (71417012), we obtain a triangular number (50345595 = T₁₀₀₃₄).

The spelling of 21071417 in words is "twenty-one million, seventy-one thousand, four hundred seventeen".