1395624721 has 4 divisors (see below), whose sum is σ = 1425318912. Its totient is φ = 1365930532.

The previous prime is 1395624709. The next prime is 1395624757. The reversal of 1395624721 is 1274265931.

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 an emirpimes, since its reverse is a distinct semiprime: 1274265931 = 223 ⋅5714197.

It is a cyclic number.

It is not a de Polignac number, because 1395624721 - 2¹³ = 1395616529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1395624701) 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, 14847025 + ... + 14847118.

It is an arithmetic number, because the mean of its divisors is an integer number (356329728).

Almost surely, 2^1395624721 is an apocalyptic number.

It is an amenable number.

1395624721 is a deficient number, since it is larger than the sum of its proper divisors (29694191).

1395624721 is an equidigital number, since it uses as much as digits as its factorization.

1395624721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29694190.

The product of its digits is 90720, while the sum is 40.

The square root of 1395624721 is about 37358.0609909026. The cubic root of 1395624721 is about 1117.5223506649.

The spelling of 1395624721 in words is "one billion, three hundred ninety-five million, six hundred twenty-four thousand, seven hundred twenty-one".