1221151971 has 8 divisors (see below), whose sum is σ = 1753449040. Its totient is φ = 751478112.

The previous prime is 1221151963. The next prime is 1221151991. The reversal of 1221151971 is 1791511221.

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

It is not a de Polignac number, because 1221151971 - 2³ = 1221151963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221151991) 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, 15655756 + ... + 15655833.

It is an arithmetic number, because the mean of its divisors is an integer number (219181130).

Almost surely, 2^1221151971 is an apocalyptic number.

1221151971 is a deficient number, since it is larger than the sum of its proper divisors (532297069).

1221151971 is a wasteful number, since it uses less digits than its factorization.

1221151971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31311605.

The product of its digits is 1260, while the sum is 30.

The square root of 1221151971 is about 34944.9849191554. The cubic root of 1221151971 is about 1068.8659399956.

The spelling of 1221151971 in words is "one billion, two hundred twenty-one million, one hundred fifty-one thousand, nine hundred seventy-one".