15551399381 has 8 divisors (see below), whose sum is σ = 17773789824. Its totient is φ = 13329199440.

The previous prime is 15551399363. The next prime is 15551399399. The reversal of 15551399381 is 18399315551.

It is an interprime number because it is at equal distance from previous prime (15551399363) and next prime (15551399399).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15551399381 - 2¹⁸ = 15551137237 is a prime.

It is a super-2 number, since 2×15551399381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15551399341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 258551 + ... + 312971.

It is an arithmetic number, because the mean of its divisors is an integer number (2221723728).

Almost surely, 2^15551399381 is an apocalyptic number.

It is an amenable number.

15551399381 is a deficient number, since it is larger than the sum of its proper divisors (2222390443).

15551399381 is an equidigital number, since it uses as much as digits as its factorization.

15551399381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95251.

The product of its digits is 729000, while the sum is 50.

The spelling of 15551399381 in words is "fifteen billion, five hundred fifty-one million, three hundred ninety-nine thousand, three hundred eighty-one".