820581630 has 32 divisors (see below), whose sum is σ = 2148432768. Its totient is φ = 198928800.

The previous prime is 820581607. The next prime is 820581631. The reversal of 820581630 is 36185028.

It is a happy number.

It is a super-2 number, since 2×820581630² = 1346708422986913800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 820581591 and 820581600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820581631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1242976 + ... + 1243635.

It is an arithmetic number, because the mean of its divisors is an integer number (67138524).

Almost surely, 2^820581630 is an apocalyptic number.

820581630 is an abundant number, since it is smaller than the sum of its proper divisors (1327851138).

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

820581630 is a wasteful number, since it uses less digits than its factorization.

820581630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2486632.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 820581630 is about 28645.7960266424. The cubic root of 820581630 is about 936.2114108075.

The spelling of 820581630 in words is "eight hundred twenty million, five hundred eighty-one thousand, six hundred thirty".