1621831123 has 12 divisors (see below), whose sum is σ = 1840183744. Its totient is φ = 1426827600.

The previous prime is 1621831109. The next prime is 1621831147. The reversal of 1621831123 is 3211381261.

It is a happy number.

It is not a de Polignac number, because 1621831123 - 2⁵ = 1621831091 is a prime.

It is a super-2 number, since 2×1621831123² = 5260672383062882258, which contains 22 as substring.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1621831091 and 1621831100.

It is not an unprimeable number, because it can be changed into a prime (1621831153) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 212436 + ... + 219937.

Almost surely, 2^1621831123 is an apocalyptic number.

1621831123 is a deficient number, since it is larger than the sum of its proper divisors (218352621).

1621831123 is a wasteful number, since it uses less digits than its factorization.

1621831123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432426 (or 432415 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 1621831123 is about 40271.9644790268. The cubic root of 1621831123 is about 1174.9026321611.

It can be divided in two parts, 162183 and 1123, that added together give a triangular number (163306 = T₅₇₁).

The spelling of 1621831123 in words is "one billion, six hundred twenty-one million, eight hundred thirty-one thousand, one hundred twenty-three".