1821986451 has 24 divisors (see below), whose sum is σ = 2760881760. Its totient is φ = 1156243200.

The previous prime is 1821986431. The next prime is 1821986483. The reversal of 1821986451 is 1546891281.

It is a happy number.

1821986451 is a `hidden beast` number, since 1 + 8 + 2 + 198 + 6 + 451 = 666.

It is not a de Polignac number, because 1821986451 - 2⁹ = 1821985939 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 1821986397 and 1821986406.

It is not an unprimeable number, because it can be changed into a prime (1821986431) 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, 30630 + ... + 67691.

It is an arithmetic number, because the mean of its divisors is an integer number (115036740).

Almost surely, 2^1821986451 is an apocalyptic number.

1821986451 is a deficient number, since it is larger than the sum of its proper divisors (938895309).

1821986451 is a wasteful number, since it uses less digits than its factorization.

1821986451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98427 (or 98424 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The square root of 1821986451 is about 42684.7332309808. The cubic root of 1821986451 is about 1221.3731852943.

The spelling of 1821986451 in words is "one billion, eight hundred twenty-one million, nine hundred eighty-six thousand, four hundred fifty-one".