1221519951 has 12 divisors (see below), whose sum is σ = 1781549328. Its totient is φ = 806439744.

The previous prime is 1221519931. The next prime is 1221519953. The reversal of 1221519951 is 1599151221.

It is not a de Polignac number, because 1221519951 - 2⁵ = 1221519919 is a prime.

It is a super-2 number, since 2×1221519951² = 2984221981382084802, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221519953) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 657930 + ... + 659783.

It is an arithmetic number, because the mean of its divisors is an integer number (148462444).

Almost surely, 2^1221519951 is an apocalyptic number.

1221519951 is a deficient number, since it is larger than the sum of its proper divisors (560029377).

1221519951 is a wasteful number, since it uses less digits than its factorization.

1221519951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1317822 (or 1317819 counting only the distinct ones).

The product of its digits is 8100, while the sum is 36.

The square root of 1221519951 is about 34950.2496557607. The cubic root of 1221519951 is about 1068.9732926694.

The spelling of 1221519951 in words is "one billion, two hundred twenty-one million, five hundred nineteen thousand, nine hundred fifty-one".