21500030 has 16 divisors (see below), whose sum is σ = 38806560. Its totient is φ = 8576352.

The previous prime is 21500029. The next prime is 21500069. The reversal of 21500030 is 3000512.

It is a junction number, because it is equal to n+sod(n) for n = 21499984 and 21500020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1127 + ... + 6653.

It is an arithmetic number, because the mean of its divisors is an integer number (2425410).

Almost surely, 2^21500030 is an apocalyptic number.

21500030 is a deficient number, since it is larger than the sum of its proper divisors (17306530).

21500030 is a wasteful number, since it uses less digits than its factorization.

21500030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5923.

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 21500030 is about 4636.8124827299. The cubic root of 21500030 is about 278.0650176585.

Adding to 21500030 its reverse (3000512), we get a palindrome (24500542).

The spelling of 21500030 in words is "twenty-one million, five hundred thousand, thirty".