661969445 has 4 divisors (see below), whose sum is σ = 794363340. Its totient is φ = 529575552.

The previous prime is 661969433. The next prime is 661969459. The reversal of 661969445 is 544969166.

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 468592609 + 193376836 = 21647^2 + 13906^2 .

It is a cyclic number.

It is not a de Polignac number, because 661969445 - 2²² = 657775141 is a prime.

It is a super-2 number, since 2×661969445² = 876407092227216050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661969393 and 661969402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66196940 + ... + 66196949.

It is an arithmetic number, because the mean of its divisors is an integer number (198590835).

Almost surely, 2^661969445 is an apocalyptic number.

It is an amenable number.

661969445 is a deficient number, since it is larger than the sum of its proper divisors (132393895).

661969445 is a wasteful number, since it uses less digits than its factorization.

661969445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132393894.

The product of its digits is 1399680, while the sum is 50.

The square root of 661969445 is about 25728.7668767860. The cubic root of 661969445 is about 871.5239265960.

The spelling of 661969445 in words is "six hundred sixty-one million, nine hundred sixty-nine thousand, four hundred forty-five".