661220547 has 16 divisors (see below), whose sum is σ = 956928000. Its totient is φ = 403697952.

The previous prime is 661220543. The next prime is 661220563. The reversal of 661220547 is 745022166.

It is not a de Polignac number, because 661220547 - 2² = 661220543 is a prime.

It is a super-2 number, since 2×661220547² = 874425223549958418, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661220543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61797 + ... + 71702.

It is an arithmetic number, because the mean of its divisors is an integer number (59808000).

Almost surely, 2^661220547 is an apocalyptic number.

661220547 is a deficient number, since it is larger than the sum of its proper divisors (295707453).

661220547 is a wasteful number, since it uses less digits than its factorization.

661220547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133642.

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 661220547 is about 25714.2090486952. The cubic root of 661220547 is about 871.1951456551.

The spelling of 661220547 in words is "six hundred sixty-one million, two hundred twenty thousand, five hundred forty-seven".