21653151 has 8 divisors (see below), whose sum is σ = 31091760. Its totient is φ = 13324992.

The previous prime is 21653131. The next prime is 21653153. The reversal of 21653151 is 15135612.

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

It is not a de Polignac number, because 21653151 - 2⁹ = 21652639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653153) 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, 277566 + ... + 277643.

It is an arithmetic number, because the mean of its divisors is an integer number (3886470).

Almost surely, 2^21653151 is an apocalyptic number.

21653151 is a deficient number, since it is larger than the sum of its proper divisors (9438609).

21653151 is a wasteful number, since it uses less digits than its factorization.

21653151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555225.

The product of its digits is 900, while the sum is 24.

The square root of 21653151 is about 4653.2946392852. The cubic root of 21653151 is about 278.7235735436.

Adding to 21653151 its reverse (15135612), we get a palindrome (36788763).

The spelling of 21653151 in words is "twenty-one million, six hundred fifty-three thousand, one hundred fifty-one".