1272197820 has 96 divisors (see below), whose sum is σ = 3756775680. Its totient is φ = 320785920.

The previous prime is 1272197819. The next prime is 1272197837. The reversal of 1272197820 is 287912721.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1085835 + ... + 1087005.

It is an arithmetic number, because the mean of its divisors is an integer number (39133080).

Almost surely, 2^1272197820 is an apocalyptic number.

1272197820 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 1272197820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1878387840).

1272197820 is an abundant number, since it is smaller than the sum of its proper divisors (2484577860).

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

1272197820 is a wasteful number, since it uses less digits than its factorization.

1272197820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2155 (or 2153 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 39.

The square root of 1272197820 is about 35667.8821911254. The cubic root of 1272197820 is about 1083.5564683308.

The spelling of 1272197820 in words is "one billion, two hundred seventy-two million, one hundred ninety-seven thousand, eight hundred twenty".