1221001764 has 12 divisors (see below), whose sum is σ = 2849004144. Its totient is φ = 407000584.

The previous prime is 1221001763. The next prime is 1221001777. The reversal of 1221001764 is 4671001221.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×1221001764² = 2981690615382223392, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221001763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50875062 + ... + 50875085.

It is an arithmetic number, because the mean of its divisors is an integer number (237417012).

Almost surely, 2^1221001764 is an apocalyptic number.

It is an amenable number.

1221001764 is an abundant number, since it is smaller than the sum of its proper divisors (1628002380).

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

1221001764 is a wasteful number, since it uses less digits than its factorization.

1221001764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101750154 (or 101750152 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 1221001764 is about 34942.8356605471. The cubic root of 1221001764 is about 1068.8221131465.

Adding to 1221001764 its reverse (4671001221), we get a palindrome (5892002985).

The spelling of 1221001764 in words is "one billion, two hundred twenty-one million, one thousand, seven hundred sixty-four".