21820655770 has 8 divisors (see below), whose sum is σ = 39277180404. Its totient is φ = 8728262304.

The previous prime is 21820655719. The next prime is 21820655819. The reversal of 21820655770 is 7755602812.

It can be written as a sum of positive squares in 2 ways, for example, as 19585162809 + 2235492961 = 139947^2 + 47281^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21820655770² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1091032779 + ... + 1091032798.

Almost surely, 2^21820655770 is an apocalyptic number.

21820655770 is a deficient number, since it is larger than the sum of its proper divisors (17456524634).

21820655770 is a wasteful number, since it uses less digits than its factorization.

21820655770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2182065584.

The product of its (nonzero) digits is 235200, while the sum is 43.

The spelling of 21820655770 in words is "twenty-one billion, eight hundred twenty million, six hundred fifty-five thousand, seven hundred seventy".