745620221 has 4 divisors (see below), whose sum is σ = 789480252. Its totient is φ = 701760192.

The previous prime is 745620179. The next prime is 745620223. The reversal of 745620221 is 122026547.

It is a happy number.

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 655104025 + 90516196 = 25595^2 + 9514^2 .

It is a cyclic number.

It is not a de Polignac number, because 745620221 - 2⁶ = 745620157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (745620223) 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, 21929990 + ... + 21930023.

It is an arithmetic number, because the mean of its divisors is an integer number (197370063).

Almost surely, 2^745620221 is an apocalyptic number.

It is an amenable number.

745620221 is a deficient number, since it is larger than the sum of its proper divisors (43860031).

745620221 is a wasteful number, since it uses less digits than its factorization.

745620221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43860030.

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 745620221 is about 27306.0473338783. The cubic root of 745620221 is about 906.7882677487.

Adding to 745620221 its reverse (122026547), we get a palindrome (867646768).

The spelling of 745620221 in words is "seven hundred forty-five million, six hundred twenty thousand, two hundred twenty-one".