21036501 has 6 divisors (see below), whose sum is σ = 30386070. Its totient is φ = 14024328.

The previous prime is 21036493. The next prime is 21036511. The reversal of 21036501 is 10563012.

21036501 is a `hidden beast` number, since 2 + 10 + 3 + 650 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20711601 + 324900 = 4551^2 + 570^2 .

It is not a de Polignac number, because 21036501 - 2³ = 21036493 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1168686 + ... + 1168703.

It is an arithmetic number, because the mean of its divisors is an integer number (5064345).

Almost surely, 2^21036501 is an apocalyptic number.

It is an amenable number.

21036501 is a deficient number, since it is larger than the sum of its proper divisors (9349569).

21036501 is a wasteful number, since it uses less digits than its factorization.

21036501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2337395 (or 2337392 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 21036501 is about 4586.5565514883. The cubic root of 21036501 is about 276.0521719269.

Adding to 21036501 its reverse (10563012), we get a palindrome (31599513).

The spelling of 21036501 in words is "twenty-one million, thirty-six thousand, five hundred one".