1551240621 has 24 divisors (see below), whose sum is σ = 2573667200. Its totient is φ = 881961696.

The previous prime is 1551240619. The next prime is 1551240631. The reversal of 1551240621 is 1260421551.

1551240621 is a `hidden beast` number, since 15 + 5 + 1 + 24 + 0 + 621 = 666.

It is not a de Polignac number, because 1551240621 - 2¹ = 1551240619 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551240631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49330 + ... + 74403.

Almost surely, 2^1551240621 is an apocalyptic number.

It is an amenable number.

1551240621 is a deficient number, since it is larger than the sum of its proper divisors (1022426579).

1551240621 is a wasteful number, since it uses less digits than its factorization.

1551240621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123945 (or 123942 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 1551240621 is about 39385.7921210174. The cubic root of 1551240621 is about 1157.6032113494.

The spelling of 1551240621 in words is "one billion, five hundred fifty-one million, two hundred forty thousand, six hundred twenty-one".