1221572154 has 16 divisors (see below), whose sum is σ = 2665248480. Its totient is φ = 370173360.

The previous prime is 1221572141. The next prime is 1221572189. The reversal of 1221572154 is 4512751221.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9254269 + ... + 9254400.

It is an arithmetic number, because the mean of its divisors is an integer number (166578030).

Almost surely, 2^1221572154 is an apocalyptic number.

1221572154 is an abundant number, since it is smaller than the sum of its proper divisors (1443676326).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221572154 is a wasteful number, since it uses less digits than its factorization.

1221572154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18508685.

The product of its digits is 5600, while the sum is 30.

The square root of 1221572154 is about 34950.9964664815. The cubic root of 1221572154 is about 1068.9885203693.

It can be divided in two parts, 1221 and 572154, that added together give a palindrome (573375).

The spelling of 1221572154 in words is "one billion, two hundred twenty-one million, five hundred seventy-two thousand, one hundred fifty-four".