1221276381 has 8 divisors (see below), whose sum is σ = 1753627680. Its totient is φ = 751554672.

The previous prime is 1221276361. The next prime is 1221276383. The reversal of 1221276381 is 1836721221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221276381 - 2⁶ = 1221276317 is a prime.

It is a super-2 number, since 2×1221276381² = 2983031997576914322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221276383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15657351 + ... + 15657428.

It is an arithmetic number, because the mean of its divisors is an integer number (219203460).

Almost surely, 2^1221276381 is an apocalyptic number.

It is an amenable number.

1221276381 is a deficient number, since it is larger than the sum of its proper divisors (532351299).

1221276381 is a wasteful number, since it uses less digits than its factorization.

1221276381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31314795.

The product of its digits is 8064, while the sum is 33.

The square root of 1221276381 is about 34946.7649575751. The cubic root of 1221276381 is about 1068.9022371694.

The spelling of 1221276381 in words is "one billion, two hundred twenty-one million, two hundred seventy-six thousand, three hundred eighty-one".