1221831 has 24 divisors (see below), whose sum is σ = 1982960. Its totient is φ = 739152.

The previous prime is 1221823. The next prime is 1221853. The reversal of 1221831 is 1381221.

It is not a de Polignac number, because 1221831 - 2³ = 1221823 is a prime.

It is a super-2 number, since 2×1221831² = 2985741985122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20680 + ... + 20738.

2^1221831 is an apocalyptic number.

1221831 is a deficient number, since it is larger than the sum of its proper divisors (761129).

1221831 is an equidigital number, since it uses as much as digits as its factorization.

1221831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140 (or 75 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 1221831 is about 1105.3646457165. The cubic root of 1221831 is about 106.9064019760.

It can be divided in two parts, 122 and 1831, that added together give a triangular number (1953 = T₆₂).

The spelling of 1221831 in words is "one million, two hundred twenty-one thousand, eight hundred thirty-one".