21705151770 has 32 divisors (see below), whose sum is σ = 57880405440. Its totient is φ = 5788040400.

The previous prime is 21705151687. The next prime is 21705151807. The reversal of 21705151770 is 7715150712.

21705151770 is a `hidden beast` number, since 2 + 1 + 70 + 5 + 1 + 517 + 70 = 666.

It is a super-2 number, since 2×21705151770² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40194456 + ... + 40194995.

It is an arithmetic number, because the mean of its divisors is an integer number (1808762670).

Almost surely, 2^21705151770 is an apocalyptic number.

21705151770 is an abundant number, since it is smaller than the sum of its proper divisors (36175253670).

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

21705151770 is a wasteful number, since it uses less digits than its factorization.

21705151770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80389467 (or 80389461 counting only the distinct ones).

The product of its (nonzero) digits is 17150, while the sum is 36.

The spelling of 21705151770 in words is "twenty-one billion, seven hundred five million, one hundred fifty-one thousand, seven hundred seventy".