1221654431 has 4 divisors (see below), whose sum is σ = 1223397864. Its totient is φ = 1219911000.

The previous prime is 1221654373. The next prime is 1221654439. The reversal of 1221654431 is 1344561221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221654431 - 2⁶ = 1221654367 is a prime.

It is a super-2 number, since 2×1221654431² = 2984879097563867522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221654394 and 1221654403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221654439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 870665 + ... + 872066.

It is an arithmetic number, because the mean of its divisors is an integer number (305849466).

Almost surely, 2^1221654431 is an apocalyptic number.

1221654431 is a deficient number, since it is larger than the sum of its proper divisors (1743433).

1221654431 is an equidigital number, since it uses as much as digits as its factorization.

1221654431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1743432.

The product of its digits is 5760, while the sum is 29.

The square root of 1221654431 is about 34952.1734803431. The cubic root of 1221654431 is about 1069.0125198233.

The spelling of 1221654431 in words is "one billion, two hundred twenty-one million, six hundred fifty-four thousand, four hundred thirty-one".