1221516157 has 8 divisors (see below), whose sum is σ = 1291675392. Its totient is φ = 1153279200.

The previous prime is 1221516143. The next prime is 1221516169. The reversal of 1221516157 is 7516151221.

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 1221516157 - 2¹¹ = 1221514109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221516757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 479263 + ... + 481804.

It is an arithmetic number, because the mean of its divisors is an integer number (161459424).

Almost surely, 2^1221516157 is an apocalyptic number.

It is an amenable number.

1221516157 is a deficient number, since it is larger than the sum of its proper divisors (70159235).

1221516157 is an equidigital number, since it uses as much as digits as its factorization.

1221516157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961139.

The product of its digits is 4200, while the sum is 31.

The square root of 1221516157 is about 34950.1953785669. The cubic root of 1221516157 is about 1068.9721859365.

Adding to 1221516157 its reverse (7516151221), we get a palindrome (8737667378).

The spelling of 1221516157 in words is "one billion, two hundred twenty-one million, five hundred sixteen thousand, one hundred fifty-seven".