1221020023 has 4 divisors (see below), whose sum is σ = 1221385608. Its totient is φ = 1220654440.

The previous prime is 1221019979. The next prime is 1221020069. The reversal of 1221020023 is 3200201221.

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 1221020023 - 2²¹ = 1218922871 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221019985 and 1221020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020093) 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, 177736 + ... + 184477.

It is an arithmetic number, because the mean of its divisors is an integer number (305346402).

Almost surely, 2^1221020023 is an apocalyptic number.

1221020023 is a deficient number, since it is larger than the sum of its proper divisors (365585).

1221020023 is an equidigital number, since it uses as much as digits as its factorization.

1221020023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365584.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 1221020023 is about 34943.0969291504. The cubic root of 1221020023 is about 1068.8274408826.

Adding to 1221020023 its reverse (3200201221), we get a palindrome (4421221244).

The spelling of 1221020023 in words is "one billion, two hundred twenty-one million, twenty thousand, twenty-three".