1166621820 has 192 divisors, whose sum is σ = 4114682880. Its totient is φ = 240371712.

The previous prime is 1166621789. The next prime is 1166621851. The reversal of 1166621820 is 281266611.

It is an interprime number because it is at equal distance from previous prime (1166621789) and next prime (1166621851).

It is a super-3 number, since 3×1166621820³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 232296 + ... + 237264.

It is an arithmetic number, because the mean of its divisors is an integer number (21430640).

Almost surely, 2^1166621820 is an apocalyptic number.

1166621820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1166621820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2057341440).

1166621820 is an abundant number, since it is smaller than the sum of its proper divisors (2948061060).

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

1166621820 is a wasteful number, since it uses less digits than its factorization.

1166621820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5044 (or 5042 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 1166621820 is about 34155.8460589106. The cubic root of 1166621820 is about 1052.7131104997.

The spelling of 1166621820 in words is "one billion, one hundred sixty-six million, six hundred twenty-one thousand, eight hundred twenty".