21820630 has 32 divisors (see below), whose sum is σ = 43110144. Its totient is φ = 7902336.

The previous prime is 21820613. The next prime is 21820633. The reversal of 21820630 is 3602812.

It is a super-2 number, since 2×21820630² = 952279787193800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21820633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5307 + ... + 8473.

It is an arithmetic number, because the mean of its divisors is an integer number (1347192).

Almost surely, 2^21820630 is an apocalyptic number.

21820630 is a deficient number, since it is larger than the sum of its proper divisors (21289514).

21820630 is a wasteful number, since it uses less digits than its factorization.

21820630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3240.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21820630 is about 4671.2557198252. The cubic root of 21820630 is about 279.4403361712.

The spelling of 21820630 in words is "twenty-one million, eight hundred twenty thousand, six hundred thirty".