1971296820 has 144 divisors (see below), whose sum is σ = 6216537600. Its totient is φ = 505094400.

The previous prime is 1971296819. The next prime is 1971296861. The reversal of 1971296820 is 286921791.

It is a super-2 number, since 2×1971296820² = 7772022305084224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 830235 + ... + 832605.

It is an arithmetic number, because the mean of its divisors is an integer number (43170400).

Almost surely, 2^1971296820 is an apocalyptic number.

1971296820 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 1971296820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3108268800).

1971296820 is an abundant number, since it is smaller than the sum of its proper divisors (4245240780).

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

1971296820 is a wasteful number, since it uses less digits than its factorization.

1971296820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2566 (or 2561 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 1971296820 is about 44399.2885078128. The cubic root of 1971296820 is about 1253.8646939318.

The spelling of 1971296820 in words is "one billion, nine hundred seventy-one million, two hundred ninety-six thousand, eight hundred twenty".