21357030 has 32 divisors (see below), whose sum is σ = 51404544. Its totient is φ = 5678816.

The previous prime is 21356989. The next prime is 21357031. The reversal of 21357030 is 3075312.

It is a happy number.

It is a super-2 number, since 2×21357030² = 912245460841800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21356988 and 21357006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21357031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12487 + ... + 14093.

It is an arithmetic number, because the mean of its divisors is an integer number (1606392).

Almost surely, 2^21357030 is an apocalyptic number.

21357030 is an abundant number, since it is smaller than the sum of its proper divisors (30047514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21357030 is a wasteful number, since it uses less digits than its factorization.

21357030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2060.

The product of its (nonzero) digits is 630, while the sum is 21.

The square root of 21357030 is about 4621.3666809722. The cubic root of 21357030 is about 277.4471614355.

The spelling of 21357030 in words is "twenty-one million, three hundred fifty-seven thousand, thirty".