145407721 has 2 divisors, whose sum is σ = 145407722. Its totient is φ = 145407720.

The previous prime is 145407719. The next prime is 145407737. The reversal of 145407721 is 127704541.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143880025 + 1527696 = 11995^2 + 1236^2 .

It is a cyclic number.

It is not a de Polignac number, because 145407721 - 2¹ = 145407719 is a prime.

It is a super-2 number, since 2×145407721² = 42286810652827682, which contains 22 as substring.

Together with 145407719, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (145407121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72703860 + 72703861.

It is an arithmetic number, because the mean of its divisors is an integer number (72703861).

Almost surely, 2^145407721 is an apocalyptic number.

It is an amenable number.

145407721 is a deficient number, since it is larger than the sum of its proper divisors (1).

145407721 is an equidigital number, since it uses as much as digits as its factorization.

145407721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7840, while the sum is 31.

The square root of 145407721 is about 12058.5123875211. The cubic root of 145407721 is about 525.8507397915.

The spelling of 145407721 in words is "one hundred forty-five million, four hundred seven thousand, seven hundred twenty-one".