1221623501 has 8 divisors (see below), whose sum is σ = 1397342784. Its totient is φ = 1046204640.

The previous prime is 1221623489. The next prime is 1221623527. The reversal of 1221623501 is 1053261221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221623501 - 2¹⁸ = 1221361357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221623581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66320 + ... + 82713.

It is an arithmetic number, because the mean of its divisors is an integer number (174667848).

Almost surely, 2^1221623501 is an apocalyptic number.

It is an amenable number.

1221623501 is a deficient number, since it is larger than the sum of its proper divisors (175719283).

1221623501 is a wasteful number, since it uses less digits than its factorization.

1221623501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150211.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1221623501 is about 34951.7310157880. The cubic root of 1221623501 is about 1069.0034979495.

Adding to 1221623501 its reverse (1053261221), we get a palindrome (2274884722).

The spelling of 1221623501 in words is "one billion, two hundred twenty-one million, six hundred twenty-three thousand, five hundred one".