1221731370 has 32 divisors (see below), whose sum is σ = 3257951040. Its totient is φ = 325794960.

The previous prime is 1221731347. The next prime is 1221731389. The reversal of 1221731370 is 731371221.

1221731370 is a `hidden beast` number, since 1 + 221 + 73 + 1 + 370 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2262196 + ... + 2262735.

It is an arithmetic number, because the mean of its divisors is an integer number (101810970).

Almost surely, 2^1221731370 is an apocalyptic number.

1221731370 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221731370 is an abundant number, since it is smaller than the sum of its proper divisors (2036219670).

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

1221731370 is a wasteful number, since it uses less digits than its factorization.

1221731370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4524947 (or 4524941 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 1221731370 is about 34953.2740955694. The cubic root of 1221731370 is about 1069.0349612561.

The spelling of 1221731370 in words is "one billion, two hundred twenty-one million, seven hundred thirty-one thousand, three hundred seventy".