2391487981 has 8 divisors (see below), whose sum is σ = 2482412544. Its totient is φ = 2302231920.

The previous prime is 2391487961. The next prime is 2391487993. The reversal of 2391487981 is 1897841932.

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

It is a cyclic number.

It is not a de Polignac number, because 2391487981 - 2¹¹ = 2391485933 is a prime.

It is a super-2 number, since 2×2391487981² = 11438429526534912722, 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 (2391487961) 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, 414205 + ... + 419938.

It is an arithmetic number, because the mean of its divisors is an integer number (310301568).

Almost surely, 2^2391487981 is an apocalyptic number.

It is an amenable number.

2391487981 is a deficient number, since it is larger than the sum of its proper divisors (90924563).

2391487981 is an equidigital number, since it uses as much as digits as its factorization.

2391487981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834251.

The product of its digits is 870912, while the sum is 52.

The square root of 2391487981 is about 48902.8422589117. The cubic root of 2391487981 is about 1337.2811846422.

The spelling of 2391487981 in words is "two billion, three hundred ninety-one million, four hundred eighty-seven thousand, nine hundred eighty-one".