21197770 has 32 divisors (see below), whose sum is σ = 42037056. Its totient is φ = 7632000.

The previous prime is 21197767. The next prime is 21197773. The reversal of 21197770 is 7779112.

It is an interprime number because it is at equal distance from previous prime (21197767) and next prime (21197773).

It is not an unprimeable number, because it can be changed into a prime (21197773) 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, 10870 + ... + 12670.

It is an arithmetic number, because the mean of its divisors is an integer number (1313658).

Almost surely, 2^21197770 is an apocalyptic number.

21197770 is a deficient number, since it is larger than the sum of its proper divisors (20839286).

21197770 is a wasteful number, since it uses less digits than its factorization.

21197770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1926.

The product of its (nonzero) digits is 6174, while the sum is 34.

The square root of 21197770 is about 4604.1036043947. The cubic root of 21197770 is about 276.7557961895.

It can be divided in two parts, 2119 and 7770, that added together give a palindrome (9889).

The spelling of 21197770 in words is "twenty-one million, one hundred ninety-seven thousand, seven hundred seventy".