1221021423 has 48 divisors (see below), whose sum is σ = 1885459680. Its totient is φ = 759967488.

The previous prime is 1221021407. The next prime is 1221021437. The reversal of 1221021423 is 3241201221.

It is a happy number.

1221021423 is a `hidden beast` number, since 1 + 221 + 0 + 21 + 423 = 666.

It is not a de Polignac number, because 1221021423 - 2⁴ = 1221021407 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221021396 and 1221021405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221021223) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2191861 + ... + 2192417.

It is an arithmetic number, because the mean of its divisors is an integer number (39280410).

Almost surely, 2^1221021423 is an apocalyptic number.

1221021423 is a deficient number, since it is larger than the sum of its proper divisors (664438257).

1221021423 is a wasteful number, since it uses less digits than its factorization.

1221021423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 856 (or 853 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221021423 is about 34943.1169617136. The cubic root of 1221021423 is about 1068.8278493820.

Adding to 1221021423 its reverse (3241201221), we get a palindrome (4462222644).

It can be divided in two parts, 12210 and 21423, that added together give a palindrome (33633).

The spelling of 1221021423 in words is "one billion, two hundred twenty-one million, twenty-one thousand, four hundred twenty-three".