145561993 has 2 divisors, whose sum is σ = 145561994. Its totient is φ = 145561992.

The previous prime is 145561987. The next prime is 145562029. The reversal of 145561993 is 399165541.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119836809 + 25725184 = 10947^2 + 5072^2 .

It is a cyclic number.

It is not a de Polignac number, because 145561993 - 2¹³ = 145553801 is a prime.

It is a super-2 number, since 2×145561993² = 42376587612264098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (145561943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72780996 + 72780997.

It is an arithmetic number, because the mean of its divisors is an integer number (72780997).

Almost surely, 2^145561993 is an apocalyptic number.

It is an amenable number.

145561993 is a deficient number, since it is larger than the sum of its proper divisors (1).

145561993 is an equidigital number, since it uses as much as digits as its factorization.

145561993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145800, while the sum is 43.

The square root of 145561993 is about 12064.9075006815. The cubic root of 145561993 is about 526.0366431989.

The spelling of 145561993 in words is "one hundred forty-five million, five hundred sixty-one thousand, nine hundred ninety-three".