21036651 has 8 divisors (see below), whose sum is σ = 29268480. Its totient is φ = 13414632.

The previous prime is 21036647. The next prime is 21036671. The reversal of 21036651 is 15663012.

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

It is not a de Polignac number, because 21036651 - 2² = 21036647 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21036611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 152371 + ... + 152508.

It is an arithmetic number, because the mean of its divisors is an integer number (3658560).

Almost surely, 2^21036651 is an apocalyptic number.

21036651 is a deficient number, since it is larger than the sum of its proper divisors (8231829).

21036651 is a wasteful number, since it uses less digits than its factorization.

21036651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304905.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21036651 is about 4586.5729035959. The cubic root of 21036651 is about 276.0528280520.

Adding to 21036651 its reverse (15663012), we get a palindrome (36699663).

The spelling of 21036651 in words is "twenty-one million, thirty-six thousand, six hundred fifty-one".