1630243981 has 8 divisors (see below), whose sum is σ = 1635546528. Its totient is φ = 1624950000.

The previous prime is 1630243969. The next prime is 1630243991. The reversal of 1630243981 is 1893420361.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1630243981 is a prime.

It is a super-2 number, since 2×1630243981² = 5315390875173456722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1630243981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1630243991) 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, 723106 + ... + 725356.

It is an arithmetic number, because the mean of its divisors is an integer number (204443316).

Almost surely, 2^1630243981 is an apocalyptic number.

It is an amenable number.

1630243981 is a deficient number, since it is larger than the sum of its proper divisors (5302547).

1630243981 is a wasteful number, since it uses less digits than its factorization.

1630243981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4283.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 1630243981 is about 40376.2799301768. The cubic root of 1630243981 is about 1176.9306376589.

The spelling of 1630243981 in words is "one billion, six hundred thirty million, two hundred forty-three thousand, nine hundred eighty-one".