21320511 has 8 divisors (see below), whose sum is σ = 28586880. Its totient is φ = 14133912.

The previous prime is 21320491. The next prime is 21320513. The reversal of 21320511 is 11502312.

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

It is not a de Polignac number, because 21320511 - 2⁵ = 21320479 is a prime.

It is a super-2 number, since 2×21320511² = 909128378602242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320513) 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, 19315 + ... + 20388.

It is an arithmetic number, because the mean of its divisors is an integer number (3573360).

Almost surely, 2^21320511 is an apocalyptic number.

21320511 is a deficient number, since it is larger than the sum of its proper divisors (7266369).

21320511 is a wasteful number, since it uses less digits than its factorization.

21320511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39885.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21320511 is about 4617.4138865820. The cubic root of 21320511 is about 277.2889329204.

Adding to 21320511 its reverse (11502312), we get a palindrome (32822823).

The spelling of 21320511 in words is "twenty-one million, three hundred twenty thousand, five hundred eleven".