1221015567 has 8 divisors (see below), whose sum is σ = 1628539696. Its totient is φ = 813750912.

The previous prime is 1221015557. The next prime is 1221015581. The reversal of 1221015567 is 7655101221.

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

It is not a de Polignac number, because 1221015567 - 2⁸ = 1221015311 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 (1221015517) 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, 53608 + ... + 72909.

It is an arithmetic number, because the mean of its divisors is an integer number (203567462).

Almost surely, 2^1221015567 is an apocalyptic number.

1221015567 is a deficient number, since it is larger than the sum of its proper divisors (407524129).

1221015567 is a wasteful number, since it uses less digits than its factorization.

1221015567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129737.

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 1221015567 is about 34943.0331682869. The cubic root of 1221015567 is about 1068.8261406853.

Adding to 1221015567 its reverse (7655101221), we get a palindrome (8876116788).

The spelling of 1221015567 in words is "one billion, two hundred twenty-one million, fifteen thousand, five hundred sixty-seven".