21621035 has 16 divisors (see below), whose sum is σ = 27224640. Its totient is φ = 16452480.

The previous prime is 21621029. The next prime is 21621053. The reversal of 21621035 is 53012612.

It is not a de Polignac number, because 21621035 - 2¹² = 21616939 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21620998 and 21621016.

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 15 ways as a sum of consecutive naturals, for example, 25925 + ... + 26745.

It is an arithmetic number, because the mean of its divisors is an integer number (1701540).

Almost surely, 2^21621035 is an apocalyptic number.

21621035 is a deficient number, since it is larger than the sum of its proper divisors (5603605).

21621035 is a wasteful number, since it uses less digits than its factorization.

21621035 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21621035 is about 4649.8424704499. The cubic root of 21621035 is about 278.5857042244.

Adding to 21621035 its reverse (53012612), we get a palindrome (74633647).

It can be divided in two parts, 2162 and 1035, that multiplied together give a triangular number (2237670 = T₂₁₁₅).

The spelling of 21621035 in words is "twenty-one million, six hundred twenty-one thousand, thirty-five".