1211553045 has 24 divisors (see below), whose sum is σ = 2177806176. Its totient is φ = 646160976.

The previous prime is 1211553029. The next prime is 1211553071. The reversal of 1211553045 is 5403551121.

1211553045 is a `hidden beast` number, since 12 + 115 + 530 + 4 + 5 = 666.

It is not a de Polignac number, because 1211553045 - 2⁴ = 1211553029 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 497367 + ... + 499796.

It is an arithmetic number, because the mean of its divisors is an integer number (90741924).

Almost surely, 2^1211553045 is an apocalyptic number.

1211553045 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1211553045 is a deficient number, since it is larger than the sum of its proper divisors (966253131).

1211553045 is an frugal number, since it uses more digits than its factorization.

1211553045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997183 (or 997171 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 1211553045 is about 34807.3705556740. The cubic root of 1211553045 is about 1066.0579449463.

The spelling of 1211553045 in words is "one billion, two hundred eleven million, five hundred fifty-three thousand, forty-five".