1281220421 has 16 divisors (see below), whose sum is σ = 1430607360. Its totient is φ = 1139434560.

The previous prime is 1281220411. The next prime is 1281220427. The reversal of 1281220421 is 1240221821.

It is a cyclic number.

It is not a de Polignac number, because 1281220421 - 2¹⁴ = 1281204037 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281220427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85346 + ... + 99228.

It is an arithmetic number, because the mean of its divisors is an integer number (89412960).

Almost surely, 2^1281220421 is an apocalyptic number.

It is an amenable number.

1281220421 is a deficient number, since it is larger than the sum of its proper divisors (149386939).

1281220421 is a wasteful number, since it uses less digits than its factorization.

1281220421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14156.

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 1281220421 is about 35794.1394784118. The cubic root of 1281220421 is about 1086.1120133019.

It can be divided in two parts, 12812 and 20421, that added together give a palindrome (33233).

The spelling of 1281220421 in words is "one billion, two hundred eighty-one million, two hundred twenty thousand, four hundred twenty-one".