21002086 has 24 divisors (see below), whose sum is σ = 37547496. Its totient is φ = 8779680.

The previous prime is 21002083. The next prime is 21002099. The reversal of 21002086 is 68020012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002081) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1405 + ... + 6631.

It is an arithmetic number, because the mean of its divisors is an integer number (1564479).

Almost surely, 2^21002086 is an apocalyptic number.

21002086 is a deficient number, since it is larger than the sum of its proper divisors (16545410).

21002086 is a wasteful number, since it uses less digits than its factorization.

21002086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5284 (or 5277 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21002086 is about 4582.8032905635. The cubic root of 21002086 is about 275.9015524402.

Adding to 21002086 its reverse (68020012), we get a palindrome (89022098).

It can be divided in two parts, 2100 and 2086, that added together give a triangular number (4186 = T₉₁).

The spelling of 21002086 in words is "twenty-one million, two thousand, eighty-six".