21712015 has 8 divisors (see below), whose sum is σ = 28058688. Its totient is φ = 16033440.

The previous prime is 21711973. The next prime is 21712057. The reversal of 21712015 is 51021712.

It is an interprime number because it is at equal distance from previous prime (21711973) and next prime (21712057).

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

It is not a de Polignac number, because 21712015 - 2¹¹ = 21709967 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21711983 and 21712001.

It is a congruent number.

It is an unprimeable number.

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, 166951 + ... + 167080.

It is an arithmetic number, because the mean of its divisors is an integer number (3507336).

Almost surely, 2^21712015 is an apocalyptic number.

21712015 is a deficient number, since it is larger than the sum of its proper divisors (6346673).

21712015 is a wasteful number, since it uses less digits than its factorization.

21712015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334049.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21712015 is about 4659.6153274707. The cubic root of 21712015 is about 278.9759146400.

Adding to 21712015 its reverse (51021712), we get a palindrome (72733727).

It can be divided in two parts, 2171 and 2015, that added together give a triangular number (4186 = T₉₁).

The spelling of 21712015 in words is "twenty-one million, seven hundred twelve thousand, fifteen".