7421387521 has 4 divisors (see below), whose sum is σ = 7462389844. Its totient is φ = 7380385200.

The previous prime is 7421387509. The next prime is 7421387537. The reversal of 7421387521 is 1257831247.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 592679025 + 6828708496 = 24345^2 + 82636^2 .

It is a cyclic number.

It is not a de Polignac number, because 7421387521 - 2²¹ = 7419290369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7421327521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20500890 + ... + 20501251.

It is an arithmetic number, because the mean of its divisors is an integer number (1865597461).

Almost surely, 2^7421387521 is an apocalyptic number.

It is an amenable number.

7421387521 is a deficient number, since it is larger than the sum of its proper divisors (41002323).

7421387521 is a wasteful number, since it uses less digits than its factorization.

7421387521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41002322.

The product of its digits is 94080, while the sum is 40.

The square root of 7421387521 is about 86147.4754186099. The cubic root of 7421387521 is about 1950.5707311216.

The spelling of 7421387521 in words is "seven billion, four hundred twenty-one million, three hundred eighty-seven thousand, five hundred twenty-one".