1221543701 has 4 divisors (see below), whose sum is σ = 1396049952. Its totient is φ = 1047037452.

The previous prime is 1221543689. The next prime is 1221543749. The reversal of 1221543701 is 1073451221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221543701 - 2⁶ = 1221543637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221543901) 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, 87253115 + ... + 87253128.

It is an arithmetic number, because the mean of its divisors is an integer number (349012488).

Almost surely, 2^1221543701 is an apocalyptic number.

It is an amenable number.

1221543701 is a deficient number, since it is larger than the sum of its proper divisors (174506251).

1221543701 is an equidigital number, since it uses as much as digits as its factorization.

1221543701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174506250.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 1221543701 is about 34950.5894227837. The cubic root of 1221543701 is about 1068.9802206368.

Adding to 1221543701 its reverse (1073451221), we get a palindrome (2294994922).

The spelling of 1221543701 in words is "one billion, two hundred twenty-one million, five hundred forty-three thousand, seven hundred one".