73215421 has 2 divisors, whose sum is σ = 73215422. Its totient is φ = 73215420.

The previous prime is 73215407. The next prime is 73215427. The reversal of 73215421 is 12451237.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57927321 + 15288100 = 7611^2 + 3910^2 .

It is a cyclic number.

It is not a de Polignac number, because 73215421 - 2²⁵ = 39660989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73215427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36607710 + 36607711.

It is an arithmetic number, because the mean of its divisors is an integer number (36607711).

Almost surely, 2^73215421 is an apocalyptic number.

It is an amenable number.

73215421 is a deficient number, since it is larger than the sum of its proper divisors (1).

73215421 is an equidigital number, since it uses as much as digits as its factorization.

73215421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 73215421 is about 8556.6010190963. The cubic root of 73215421 is about 418.3446197633.

Adding to 73215421 its reverse (12451237), we get a palindrome (85666658).

The spelling of 73215421 in words is "seventy-three million, two hundred fifteen thousand, four hundred twenty-one".