21015485 has 8 divisors (see below), whose sum is σ = 26702136. Its totient is φ = 15823360.

The previous prime is 21015473. The next prime is 21015497. The reversal of 21015485 is 58451012.

It is an interprime number because it is at equal distance from previous prime (21015473) and next prime (21015497).

It can be written as a sum of positive squares in 4 ways, for example, as 10640644 + 10374841 = 3262^2 + 3221^2 .

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

It is not a de Polignac number, because 21015485 - 2¹⁴ = 20999101 is a prime.

It is a Duffinian number.

It is a Curzon number.

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, 123536 + ... + 123705.

It is an arithmetic number, because the mean of its divisors is an integer number (3337767).

Almost surely, 2^21015485 is an apocalyptic number.

It is an amenable number.

21015485 is a deficient number, since it is larger than the sum of its proper divisors (5686651).

21015485 is a wasteful number, since it uses less digits than its factorization.

21015485 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247263.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 21015485 is about 4584.2649356249. The cubic root of 21015485 is about 275.9602135816.

Adding to 21015485 its reverse (58451012), we get a palindrome (79466497).

The spelling of 21015485 in words is "twenty-one million, fifteen thousand, four hundred eighty-five".