821742770 has 32 divisors (see below), whose sum is σ = 1568796336. Its totient is φ = 308838400.

The previous prime is 821742707. The next prime is 821742791. The reversal of 821742770 is 77247128.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 484396081 + 337346689 = 22009^2 + 18367^2 .

It is a super-2 number, since 2×821742770² = 1350522360094545800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105200 + ... + 112740.

Almost surely, 2^821742770 is an apocalyptic number.

821742770 is a deficient number, since it is larger than the sum of its proper divisors (747053566).

821742770 is a wasteful number, since it uses less digits than its factorization.

821742770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8206.

The product of its (nonzero) digits is 43904, while the sum is 38.

The square root of 821742770 is about 28666.0560593884. The cubic root of 821742770 is about 936.6527888647.

Adding to 821742770 its reverse (77247128), we get a palindrome (898989898).

The spelling of 821742770 in words is "eight hundred twenty-one million, seven hundred forty-two thousand, seven hundred seventy".