21358513 has 8 divisors (see below), whose sum is σ = 24313536. Its totient is φ = 18572400.

The previous prime is 21358501. The next prime is 21358537. The reversal of 21358513 is 31585312.

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

It is not a de Polignac number, because 21358513 - 2¹³ = 21350321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21358913) 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, 41958 + ... + 42463.

It is an arithmetic number, because the mean of its divisors is an integer number (3039192).

Almost surely, 2^21358513 is an apocalyptic number.

21358513 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21358513 is a deficient number, since it is larger than the sum of its proper divisors (2955023).

21358513 is a wasteful number, since it uses less digits than its factorization.

21358513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84455.

The product of its digits is 3600, while the sum is 28.

The square root of 21358513 is about 4621.5271285583. The cubic root of 21358513 is about 277.4535831246.

It can be divided in two parts, 2135 and 8513, that added together give a cube (10648 = 22³).

The spelling of 21358513 in words is "twenty-one million, three hundred fifty-eight thousand, five hundred thirteen".