21930513 has 8 divisors (see below), whose sum is σ = 31898976. Its totient is φ = 13291200.

The previous prime is 21930511. The next prime is 21930553. The reversal of 21930513 is 31503912.

It is a happy number.

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

It is not a de Polignac number, because 21930513 - 2¹ = 21930511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21930511) 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, 332248 + ... + 332313.

It is an arithmetic number, because the mean of its divisors is an integer number (3987372).

Almost surely, 2^21930513 is an apocalyptic number.

It is an amenable number.

21930513 is a deficient number, since it is larger than the sum of its proper divisors (9968463).

21930513 is a wasteful number, since it uses less digits than its factorization.

21930513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664575.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 21930513 is about 4683.0025624593. The cubic root of 21930513 is about 279.9086138842.

Subtracting from 21930513 its sum of digits (24), we obtain a square (21930489 = 4683²).

The spelling of 21930513 in words is "twenty-one million, nine hundred thirty thousand, five hundred thirteen".