21061671 has 16 divisors (see below), whose sum is σ = 29658240. Its totient is φ = 13258080.

The previous prime is 21061669. The next prime is 21061673. The reversal of 21061671 is 17616012.

It is an interprime number because it is at equal distance from previous prime (21061669) and next prime (21061673).

It is not a de Polignac number, because 21061671 - 2¹ = 21061669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21061673) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30496 + ... + 31178.

It is an arithmetic number, because the mean of its divisors is an integer number (1853640).

Almost surely, 2^21061671 is an apocalyptic number.

21061671 is a deficient number, since it is larger than the sum of its proper divisors (8596569).

21061671 is a wasteful number, since it uses less digits than its factorization.

21061671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1246.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21061671 is about 4589.2996197677. The cubic root of 21061671 is about 276.1622260948.

Adding to 21061671 its reverse (17616012), we get a palindrome (38677683).

The spelling of 21061671 in words is "twenty-one million, sixty-one thousand, six hundred seventy-one".