21220770 has 16 divisors (see below), whose sum is σ = 50929920. Its totient is φ = 5658864.

The previous prime is 21220757. The next prime is 21220783. The reversal of 21220770 is 7702212.

It is an interprime number because it is at equal distance from previous prime (21220757) and next prime (21220783).

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, 353650 + ... + 353709.

It is an arithmetic number, because the mean of its divisors is an integer number (3183120).

Almost surely, 2^21220770 is an apocalyptic number.

21220770 is an abundant number, since it is smaller than the sum of its proper divisors (29709150).

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

21220770 is a wasteful number, since it uses less digits than its factorization.

21220770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 707369.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 21220770 is about 4606.6006989970. The cubic root of 21220770 is about 276.8558551817.

Adding to 21220770 its reverse (7702212), we get a palindrome (28922982).

The spelling of 21220770 in words is "twenty-one million, two hundred twenty thousand, seven hundred seventy".