72421649 has 4 divisors (see below), whose sum is σ = 76681764. Its totient is φ = 68161536.

The previous prime is 72421639. The next prime is 72421651. The reversal of 72421649 is 94612427.

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 68145025 + 4276624 = 8255^2 + 2068^2 .

It is a cyclic number.

It is not a de Polignac number, because 72421649 - 2¹⁶ = 72356113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72421619) 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, 2130032 + ... + 2130065.

It is an arithmetic number, because the mean of its divisors is an integer number (19170441).

Almost surely, 2^72421649 is an apocalyptic number.

It is an amenable number.

72421649 is a deficient number, since it is larger than the sum of its proper divisors (4260115).

72421649 is a wasteful number, since it uses less digits than its factorization.

72421649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4260114.

The product of its digits is 24192, while the sum is 35.

The square root of 72421649 is about 8510.0910100891. The cubic root of 72421649 is about 416.8272819364.

The spelling of 72421649 in words is "seventy-two million, four hundred twenty-one thousand, six hundred forty-nine".