1221635107 has 32 divisors (see below), whose sum is σ = 1557563904. Its totient is φ = 930508800.

The previous prime is 1221635099. The next prime is 1221635111. The reversal of 1221635107 is 7015361221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221635107 - 2³ = 1221635099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221635137) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1905507 + ... + 1906147.

It is an arithmetic number, because the mean of its divisors is an integer number (48673872).

Almost surely, 2^1221635107 is an apocalyptic number.

1221635107 is a deficient number, since it is larger than the sum of its proper divisors (335928797).

1221635107 is a wasteful number, since it uses less digits than its factorization.

1221635107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1179.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 1221635107 is about 34951.8970443666. The cubic root of 1221635107 is about 1069.0068832847.

Adding to 1221635107 its reverse (7015361221), we get a palindrome (8236996328).

The spelling of 1221635107 in words is "one billion, two hundred twenty-one million, six hundred thirty-five thousand, one hundred seven".