72400001 has 4 divisors (see below), whose sum is σ = 72417072. Its totient is φ = 72382932.

The previous prime is 72399997. The next prime is 72400019. The reversal of 72400001 is 10000427.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10000427 = 2557 ⋅3911.

It is a cyclic number.

It is not a de Polignac number, because 72400001 - 2² = 72399997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72400091) 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, 3266 + ... + 12468.

It is an arithmetic number, because the mean of its divisors is an integer number (18104268).

Almost surely, 2^72400001 is an apocalyptic number.

It is an amenable number.

72400001 is a deficient number, since it is larger than the sum of its proper divisors (17071).

72400001 is an equidigital number, since it uses as much as digits as its factorization.

72400001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17070.

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 72400001 is about 8508.8190132356. The cubic root of 72400001 is about 416.7857456630.

Adding to 72400001 its reverse (10000427), we get a palindrome (82400428).

The spelling of 72400001 in words is "seventy-two million, four hundred thousand, one".