7491421809 has 45 divisors (see below), whose sum is σ = 11454047913. Its totient is φ = 4879511928.

The previous prime is 7491421799. The next prime is 7491421843. The reversal of 7491421809 is 9081241947.

It is a happy number.

The square root of 7491421809 is 86553.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 7491421809 - 2²¹ = 7489324657 is a prime.

It is a super-2 number, since 2×7491421809² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7491421879) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 45959562 + ... + 45959724.

Almost surely, 2^7491421809 is an apocalyptic number.

7491421809 is the 86553-rd square number.

7491421809 is the 43277-th centered octagonal number.

It is an amenable number.

7491421809 is a deficient number, since it is larger than the sum of its proper divisors (3962626104).

7491421809 is an frugal number, since it uses more digits than its factorization.

7491421809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 225 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The cubic root of 7491421809 is about 1956.6872584972.

The spelling of 7491421809 in words is "seven billion, four hundred ninety-one million, four hundred twenty-one thousand, eight hundred nine".